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广东湛江二中港城中学2019-2020学年初三第二学期4月线上月考(暨期中考试)英语试题

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广东省湛江二中港城中学2019-2020学年九年级(下)开学考试物理试题(收心考试)(word无答案)

广东省湛江二中港城中学2019-2020学年九年级(下)开学考试物理试题(收心考试)(word无答案)

广东省湛江二中港城中学2019-2020学年九年级（下）开学考试物理试题（收心考试）一、单选题(★) 1 . “秋叶未尽，寒意初起。

”太原市在 11 月 1 日开始冬季供暖。

供暖系统中采用水作介质利用了水的（）A．比热容大B．热值大C．热量多D．内能多(★) 2 . 下列关于四冲程内燃机的说法中正确的是A．一个工作循环对外做功一次B．汽油机在吸气冲程中吸入气缸的是空气C．压缩冲程中将内能转化为机械能D．热机效率越高，所做的有用功就越多(★) 3 . 如图所示的电路中，下列说法中正确的是（）A．若同时闭合 S1、S2，R1、R2并联在电路中B．若同时闭合 S1、S2，则电路会发生短路C．若同时闭合 S2、S3，则R1、R2串联D．若只闭合 S1，则R1、R2并联(★) 4 . 如图所示，电源电压不变， R 1、 R 2为定值电阻且 R 1＞ R 2。

开关 S 闭合后，电流表示数最小的是（）A．B．C．D．(★) 5 . 标有“6V 3W”的小灯泡，通过它的电流与电压的关系如图所示。

若把它与一只阻值为10Ω的电阻 R串联接在电压为 8V 的电路中，电阻 R两端的电压为 4V。

则整个电路消耗的功率为（）A．2.4W B．1.6WC．0.8W D．3.2W(★★) 6 . 把标有“3V 3W”和“3V 1W”字样的甲、乙两盏灯串联接在 3V 的电源上，闭合开关后，两灯都发光，则下列分析中正确的是（不考虑灯丝电阻的变化）（）A．甲灯比乙灯亮B．只有乙灯正常发光C．电路的总功率是 4WD．电路的总功率是 0.75W(★) 7 . 图甲是小灯泡L 1和L 2的电流随电压变化的图象．将它们按图乙所示接入电路中，闭合开关S，小灯泡L 1的实际功率为1W．下面的说法中正确的是（）A．灯泡L1比L2暗B．电流表的示数为0.5AC ．电源电压为2VD ．电压为1V 时，灯泡L 1的功率为0.25W(★) 8 . 对于我们来说生命只有一次，不会重新来过，因此，生活用电必须把安全放在第一位，如图所示的各种情况下，人体不会触电的是（） A ． B ．C ．D ．(★) 9 . 如图所示电路连接中，当开关S 闭合时，下列说法正确的是A ．螺线管上端为S 极，滑片P 向左移，弹簧伸长B ．螺线管上端为N 极，滑片P 向左移，弹簧缩短C ．螺线管上端为S 极，滑片P 向右移，弹簧伸长D ．螺线管上端为N 极，滑片P 向右移，弹簧缩短二、填空题(★) 10 . 在如图 1 所示的电路中，电源电压保持不变，当开关 S 闭合，甲、乙两表为电压表时，两表的指针偏转角度相同如图 2 所示， R 1两端电压为 _____ V ， R 1: R 2＝ _____ ，当开关 S 断开，甲、乙均为电流表时，甲、乙两表示数之比为 _____ 。

广东省湛江市2019-2020学年中考第二次质量检测数学试题含解析

广东省湛江市2019-2020学年中考第二次质量检测数学试题含解析

广东省湛江市2019-2020学年中考第二次质量检测数学试题一、选择题（本大题共12个小题，每小题4分，共48分．在每小题给出的四个选项中，只有一项是符合题目要求的．）1．过正方体中有公共顶点的三条棱的中点切出一个平面，形成如图几何体，其正确展开图正确的为（ ）A ．B ．C ．D ．2．下列运算结果是无理数的是（ ）A ．32×2B ．32⨯C ．722÷D ．22135-3．如图是由三个相同的小正方体组成的几何体，则该几何体的左视图是（ ）A ．B ．C ．D ．4．运用乘法公式计算（4+x ）（4﹣x ）的结果是（ ）A ．x 2﹣16B ．16﹣x 2C ．16﹣8x+x 2D ．8﹣x 25．若ab ＜0，则正比例函数y=ax 与反比例函数y=b x在同一坐标系中的大致图象可能是（ ） A ． B ． C ． D ．6．计算（x －2）（x+5）的结果是A ．x 2+3x+7B ．x 2+3x+10C ．x 2+3x －10D ．x 2－3x －107．如图，4张如图1的长为a ，宽为b （a ＞b ）长方形纸片，按图2的方式放置，阴影部分的面积为S 1，空白部分的面积为S 2，若S 2＝2S 1，则a ，b 满足（ ）A．a＝32b B．a＝2b C．a＝52b D．a＝3b8．a、b互为相反数，则下列成立的是（）A．ab=1 B．a+b=0 C．a=b D．ab=-19．如图，在菱形ABCD中，∠A=60°，E是AB边上一动点（不与A、B重合），且∠EDF=∠A，则下列结论错误的是（）A．AE=BF B．∠ADE=∠BEFC．△DEF是等边三角形D．△BEF是等腰三角形10．如图，把一块直角三角板的直角顶点放在直尺的一边上，若∠1=50°，则∠2的度数为（）．A．50°B．40°C．30°D．25°11．已知关于x的不等式组217x ax-<⎧⎨-≥⎩至少有两个整数解，且存在以3，a，7为边的三角形，则a的整数解有（）A．4个B．5个C．6个D．7个12．到三角形三个顶点的距离相等的点是三角形（）的交点．A．三个内角平分线B．三边垂直平分线C．三条中线D．三条高二、填空题：（本大题共6个小题，每小题4分，共24分．）13．如图，这是由边长为1的等边三角形摆出的一系列图形，按这种方式摆下去，则第n个图形的周长是___．14．求1+2+22+23+…+22007的值，可令s=1+2+22+23+…+22007，则2s=2+22+23+24+…+22018，因此2s ﹣s=22018﹣1，即s=22018﹣1，仿照以上推理，计算出1+3+32+33+…+32018的值为_____．15．如图，两个三角形相似，AD=2，AE=3，EC=1，则BD=_____．16．如图，已知直线1y k x b =+与x 轴、y 轴相交于P 、Q 两点，与2k y x =的图象相交于(2,)A m -、(1,)B n 两点，连接OA 、OB .给出下列结论：①120k k <；②102m n +=；③AOP BOQ S S ∆∆=；④不等式21k k x b x +>的解集是2x <-或01x <<. 其中正确结论的序号是__________．17．今年我市初中毕业暨升学统一考试的考生约有35300人,该数据用科学记数法表示为________人. 18．如果将“概率”的英文单词 probability 中的11个字母分别写在11张相同的卡片上，字面朝下随意放在桌子上，任取一张，那么取到字母b 的概率是________．三、解答题：（本大题共9个小题，共78分，解答应写出文字说明、证明过程或演算步骤．19．（6分）某商场要经营一种新上市的文具，进价为20元，试营销阶段发现：当销售单价是25元时，每天的销售量为250件，销售单价每上涨1元，每天的销售量就减少10件写出商场销售这种文具，每天所得的销售利润（元）与销售单价（元）之间的函数关系式；求销售单价为多少元时，该文具每天的销售利润最大；商场的营销部结合上述情况，提出了A 、B 两种营销方案方案A ：该文具的销售单价高于进价且不超过30元；方案B ：每天销售量不少于10件，且每件文具的利润至少为25元请比较哪种方案的最大利润更高，并说明理由20．（6分）某电器商场销售甲、乙两种品牌空调，已知每台乙种品牌空调的进价比每台甲种品牌空调的进价高20％，用7200元购进的乙种品牌空调数量比用3000元购进的甲种品牌空调数量多2台． 求甲、乙两种品牌空调的进货价；该商场拟用不超过16000元购进甲、乙两种品牌空调共10台进行销售，其中甲种品牌空调的售价为2500元／台，乙种品牌空调的售价为3500元／台．请您帮该商场设计一种进货方案，使得在售完这10台空调后获利最大，并求出最大利润．21．（6分）如图，分别以Rt△ABC的直角边AC及斜边AB向外作等边△ACD，等边△ABE，已知∠BAC=30°，EF⊥AB，垂足为F，连接DF试说明AC=EF；求证：四边形ADFE是平行四边形．22．（8分）某种蔬菜的销售单价y1与销售月份x之间的关系如图（1）所示，成本y2与销售月份之间的关系如图（2）所示（图（1）的图象是线段图（2）的图象是抛物线）分别求出y1、y2的函数关系式（不写自变量取值范围）；通过计算说明：哪个月出售这种蔬菜，每千克的收益最大？23．（8分）如图，抛物线y=ax2+bx+c与x轴相交于点A（﹣3，0），B（1，0），与y轴相交于（0，﹣32），顶点为P．（1）求抛物线解析式；（2）在抛物线是否存在点E，使△ABP的面积等于△ABE的面积？若存在，求出符合条件的点E的坐标；若不存在，请说明理由；（3）坐标平面内是否存在点F，使得以A、B、P、F为顶点的四边形为平行四边形？直接写出所有符合条件的点F的坐标，并求出平行四边形的面积．24．（10分）如图，在平行四边形ABCD中，E、F分别在AD、BC边上，且AE＝CF．求证：四边形BFDE是平行四边形．25．（10分）如图，某人在山坡坡脚C处测得一座建筑物顶点A的仰角为63.4°，沿山坡向上走到P处再测得该建筑物顶点A的仰角为53°．已知BC＝90米，且B、C、D在同一条直线上，山坡坡度i＝5：1．(1)求此人所在位置点P的铅直高度．(结果精确到0.1米)(2)求此人从所在位置点P走到建筑物底部B点的路程(结果精确到0.1米)(测倾器的高度忽略不计，参考数据：tan53°≈43，tan63.4°≈2)26．（12分）如图，已知点D、E为△ABC的边BC上两点．AD=AE，BD=CE，为了判断∠B与∠C的大小关系，请你填空完成下面的推理过程，并在空白括号内注明推理的依据．解：过点A作AH⊥BC，垂足为H．∵在△ADE中，AD=AE（已知）AH⊥BC（所作）∴DH=EH（等腰三角形底边上的高也是底边上的中线）又∵BD=CE（已知）∴BD+DH=CE+EH（等式的性质）即：BH=又∵（所作）∴AH为线段的垂直平分线∴AB=AC（线段垂直平分线上的点到线段两个端点的距离相等）∴（等边对等角）27．（12分）如图，在平面直角坐标系中，直线y＝x+2与x轴，y轴分别交于A，B两点，点C（2，m）为直线y＝x+2上一点，直线y＝﹣12x+b过点C．求m和b的值；直线y＝﹣12x+b与x轴交于点D，动点P从点D开始以每秒1个单位的速度向x轴负方向运动．设点P的运动时间为t秒．①若点P在线段DA上，且△ACP的面积为10，求t的值；②是否存在t的值，使△ACP为等腰三角形？若存在，直接写出t的值；若不存在，请说明理由．参考答案一、选择题（本大题共12个小题，每小题4分，共48分．在每小题给出的四个选项中，只有一项是符合题目要求的．）1．B【解析】试题解析：选项,,A C D折叠后都不符合题意，只有选项B折叠后两个剪去三角形与另一个剪去的三角形交于一个顶点，与正方体三个剪去三角形交于一个顶点符合.故选B.2．B【解析】【分析】根据二次根式的运算法则即可求出答案．【详解】A选项：原式＝3×2＝6，故A不是无理数；B，故B是无理数；C6，故C不是无理数；D=12，故D不是无理数故选B．【点睛】考查二次根式的运算，解题的关键是熟练运用二次根式的运算法则，本题属于基础题型．3．C【解析】分析：细心观察图中几何体中正方体摆放的位置，根据左视图是从左面看到的图形判定则可．详解：从左边看竖直叠放2个正方形．故选：C．点睛：此题考查了几何体的三种视图和学生的空间想象能力，左视图是从物体左面看所得到的图形，解答时学生易将三种视图混淆而错误的选其它选项．4．B【解析】【分析】根据平方差公式计算即可得解．【详解】222+-=-=-，x x x x(4)(4)416故选：B．【点睛】本题主要考查了整式的乘法公式，熟练掌握平方差公式的运算是解决本题的关键.5．D【解析】【分析】根据ab＜0及正比例函数与反比例函数图象的特点，可以从a＞0，b＜0和a＜0，b＞0两方面分类讨论得出答案．【详解】解：∵ab＜0，∴分两种情况：（1）当a＞0，b＜0时，正比例函数y=ax数的图象过原点、第一、三象限，反比例函数图象在第二、四象限，无此选项；（2）当a＜0，b＞0时，正比例函数的图象过原点、第二、四象限，反比例函数图象在第一、三象限，选项D符合．故选D【点睛】本题主要考查了反比例函数的图象性质和正比例函数的图象性质，要掌握它们的性质才能灵活解题．6．C【解析】【分析】根据多项式乘以多项式的法则进行计算即可.【详解】故选：C.【点睛】考查多项式乘以多项式，掌握多项式乘以多项式的运算法则是解题的关键.7．B【解析】【分析】从图形可知空白部分的面积为S2是中间边长为（a﹣b）的正方形面积与上下两个直角边为（a+b）和b的直角三角形的面积，再与左右两个直角边为a和b的直角三角形面积的总和，阴影部分的面积为S1是大正方形面积与空白部分面积之差，再由S2＝2S1，便可得解．【详解】由图形可知，S2=（a-b）2+b（a+b）+ab=a2+2b2，S1=（a+b）2-S2=2ab-b2，∵S2＝2S1，∴a2+2b2＝2（2ab﹣b2），∴a2﹣4ab+4b2＝0，即（a﹣2b）2＝0，∴a＝2b，故选B．【点睛】本题主要考查了求阴影部分面积和因式分解，关键是正确列出阴影部分与空白部分的面积和正确进行因式分解．8．B【解析】【分析】依据相反数的概念及性质即可得．【详解】因为a、b互为相反数，所以a+b=1，故选B．【点睛】此题主要考查相反数的概念及性质．相反数的定义：只有符号不同的两个数互为相反数，1的相反数是1．9．D【解析】【分析】连接BD，可得△ADE≌△BDF，然后可证得DE=DF，AE=BF，即可得△DEF是等边三角形，然后可证得∠ADE=∠BEF．【详解】连接BD，∵四边形ABCD是菱形，∴AD=AB，∠ADB=12∠ADC，AB∥CD，∵∠A=60°，∴∠ADC=120°，∠ADB=60°，同理：∠DBF=60°，即∠A=∠DBF，∴△ABD是等边三角形，∴AD=BD，∵∠ADE+∠BDE=60°，∠BDE+∠BDF=∠EDF=60°，∴∠ADE=∠BDF，∵在△ADE和△BDF中，{ADE BDF AD BDA DBF∠=∠=∠=∠，∴△ADE≌△BDF（ASA），∴DE=DF，AE=BF，故A正确；∵∠EDF=60°，∴△EDF是等边三角形，∴C正确；∴∠DEF=60°，∴∠AED+∠BEF=120°，∵∠AED+∠ADE=180°-∠A=120°，∴∠ADE=∠BEF；故B正确．∵△ADE≌△BDF，∴AE=BF，同理：BE=CF，但BE不一定等于BF．故D错误．故选D．【点睛】本题考查了菱形的性质、等边三角形的判定与性质以及全等三角形的判定与性质，解题的关键是正确寻找全等三角形解决问题．10．B【解析】【详解】解：如图，由两直线平行，同位角相等，可求得∠3=∠1=50°，根据平角为180°可得，∠2=90°﹣50°=40°．故选B．【点睛】本题考查平行线的性质，掌握两直线平行，同位角相等是解题关键．11．A【解析】【分析】依据不等式组至少有两个整数解，即可得到a＞5，再根据存在以3，a，7为边的三角形，可得4＜a＜10，进而得出a的取值范围是5＜a＜10，即可得到a的整数解有4个．【详解】解：解不等式①，可得x＜a，解不等式②，可得x≥4，∵不等式组至少有两个整数解，∴a＞5，又∵存在以3，a，7为边的三角形，∴4＜a＜10，∴a的取值范围是5＜a＜10，∴a的整数解有4个，故选：A．【点睛】此题考查的是一元一次不等式组的解法和三角形的三边关系的运用，求不等式组的解集应遵循以下原则：同大取较大，同小取较小，小大大小中间找，大大小小解不了．12．B【解析】试题分析：根据线段垂直平分线上的点到两端点的距离相等解答．解：到三角形三个顶点的距离相等的点是三角形三边垂直平分线的交点．故选B．点评：本题考查了线段垂直平分线上的点到两端点的距离相等的性质，熟记性质是解题的关键．二、填空题：（本大题共6个小题，每小题4分，共24分．）13．2n+1【解析】观察摆放的一系列图形，可得到依次的周长分别是3，4，5，6，7，…，从中得到规律，根据规律写出第n个图形的周长．解：由已知一系列图形观察图形依次的周长分别是：（1）2+1=3，（2）2+2=4，（3）2+3=5，（4）2+4=6，（5）2+5=7，…，所以第n个图形的周长为：2+n．故答案为2+n．此题考查的是图形数字的变化类问题，关键是通过观察分析得出规律，根据规律求解．14．2019 312【解析】【分析】仿照已知方法求出所求即可．【详解】令S=1+3+32+33+…+32018，则3S=3+32+33+…+32019，因此3S ﹣S=32019﹣1，即S=2019312-． 故答案为：2019312-． 【点睛】本题考查了有理数的混合运算，熟练掌握运算法则是解答本题的关键．15．1【解析】【分析】根据相似三角形的对应边的比相等列出比例式，计算即可．【详解】∵△ADE ∽△ACB ，∴AE AB =AD AC ，即32BD +=231+， 解得：BD=1．故答案为1．【点睛】本题考查的是相似三角形的性质，掌握相似三角形的对应边的比相等是解题的关键．16．②③④【解析】分析：根据一次函数和反比例函数的性质得到k 1k 2＞0，故①错误；把A （-2，m ）、B （1，n ）代入y=2k x中得到-2m=n 故②正确；把A （-2，m ）、B （1，n ）代入y=k 1x+b 得到y=-mx-m ，求得P （-1，0），Q （0，-m ），根据三角形的面积公式即可得到S △AOP =S △BOQ ；故③正确；根据图象得到不等式k 1x+b ＞2k x 的解集是x ＜-2或0＜x ＜1，故④正确．详解：由图象知，k 1＜0，k 2＜0，∴k 1k 2＞0，故①错误；把A （-2，m ）、B （1，n ）代入y=2k x中得-2m=n ， ∴m+12n=0，故②正确； 把A （-2，m ）、B （1，n ）代入y=k 1x+b 得112m k b n k b -+⎧⎨+⎩＝＝， ∴1323n m k n m b -⎧⎪⎪⎨+⎪⎪⎩＝＝, ∵-2m=n ，∴y=-mx-m ，∵已知直线y=k 1x+b 与x 轴、y 轴相交于P 、Q 两点，∴P （-1，0），Q （0，-m ），∴OP=1，OQ=m ，∴S △AOP =12m ，S △BOQ =12m ， ∴S △AOP =S △BOQ ；故③正确；由图象知不等式k 1x+b ＞2k x 的解集是x ＜-2或0＜x ＜1，故④正确； 故答案为：②③④．点睛：本题考查了反比例函数与一次函数的交点，求两直线的交点坐标，三角形面积的计算，正确的理解题意是解题的关键．17．3.53×104【解析】科学记数法的表示形式为a×10n 的形式，其中1≤|a|<10，n 为整数．确定n 的值时，要看把原数变成a 时，小数点移动了多少位，n 的绝对值与小数点移动的位数相同．当原数绝对值>1时，n 是正数；当原数的绝对值<1时，n 是负数，35300=3.53×104，故答案为：3.53×104.18．211【解析】分析：让英文单词probability 中字母b 的个数除以字母的总个数即为所求的概率．详解：∵英文单词probability 中，一共有11个字母，其中字母b 有2个，∴任取一张，那么取到字母b 的概率为211． 故答案为211． 点睛：本题考查了概率公式，用到的知识点为：概率等于所求情况数与总情况数之比．三、解答题：（本大题共9个小题，共78分，解答应写出文字说明、证明过程或演算步骤．19．(1) w＝－10x2＋700x－10000;(2) 即销售单价为35元时，该文具每天的销售利润最大; (3) A方案利润更高.【解析】【分析】试题分析：（1）根据利润=（单价-进价）×销售量，列出函数关系式即可.（2）根据（1）式列出的函数关系式，运用配方法求最大值.（3）分别求出方案A、B中x的取值范围，然后分别求出A、B方案的最大利润，然后进行比较. 【详解】解：（1）w＝（x－20）（250－10x＋250）＝－10x2＋700x－10000.（2）∵w＝－10x2＋700x－10000＝－10（x－35）2＋2250∴当x＝35时，w有最大值2250，即销售单价为35元时，该文具每天的销售利润最大.（3）A方案利润高,理由如下：A方案中：20＜x≤30，函数w＝－10（x－35）2＋2250随x的增大而增大，∴当x=30时，w有最大值，此时，最大值为2000元.B方案中：10x50010x2025-+≥⎧⎨-≥⎩，解得x的取值范围为：45≤x≤49.∵45≤x≤49时，函数w＝－10（x－35）2＋2250随x的增大而减小，∴当x=45时，w有最大值，此时，最大值为1250元.∵2000＞1250，∴A方案利润更高20．（1）甲种品牌的进价为1500元，乙种品牌空调的进价为1800元；（2）当购进甲种品牌空调7台，乙种品牌空调3台时，售完后利润最大，最大为12100元【解析】【分析】（1）设甲种品牌空调的进货价为x元/台，则乙种品牌空调的进货价为1.2x元/台，根据数量=总价÷单价可得出关于x的分式方程，解之并检验后即可得出结论；（2）设购进甲种品牌空调a台，所获得的利润为y元，则购进乙种品牌空调（10-a）台，根据总价=单价×数量结合总价不超过16000 元，即可得出关于a的一元一次不等式，解之即可得出a的取值范围，再由总利润=单台利润×购进数量即可得出y关于a的函数关系式，利用一次函数的性质即可解决最值问题．【详解】（1）由（1）设甲种品牌的进价为x元，则乙种品牌空调的进价为（1+20%）x元，由题意，得 ()720030002120%xx =++， 解得x=1500，经检验，x=1500是原分式方程的解，乙种品牌空调的进价为（1+20%）×1500=1800（元）. 答：甲种品牌的进价为1500元，乙种品牌空调的进价为1800元；（2）设购进甲种品牌空调a 台，则购进乙种品牌空调（10-a ）台，由题意，得1500a+1800（10-a ）≤16000，解得 203≤a ， 设利润为w ，则w=（2500-1500）a+（3500-1800）（10-a ）=-700a+17000，因为-700<0，则w 随a 的增大而减少，当a=7时，w 最大，最大为12100元.答：当购进甲种品牌空调7台，乙种品牌空调3台时，售完后利润最大，最大为12100元.【点睛】本题考查了一次函数的应用、分式方程的应用以及一元一次不等式的应用，解题的关键是：（1）根据数量=总价÷单价列出关于x 的分式方程；（2）根据总利润=单台利润×购进数量找出y 关于a 的函数关系式． 21．证明见解析．【解析】【分析】（1）一方面Rt △ABC 中，由∠BAC=30°可以得到AB=2BC ，另一方面△ABE 是等边三角形，EF ⊥AB ，由此得到AE=2AF ，并且AB=2AF ，从而可证明△AFE ≌△BCA ，再根据全等三角形的性质即可证明AC=EF ．（2）根据（1）知道EF=AC ，而△ACD 是等边三角形，所以EF=AC=AD ，并且AD ⊥AB ，而EF ⊥AB ，由此得到EF ∥AD ，再根据平行四边形的判定定理即可证明四边形ADFE 是平行四边形．【详解】证明：（1）∵Rt △ABC 中，∠BAC=30°，∴AB=2BC ．又∵△ABE 是等边三角形，EF ⊥AB ，∴AB=2AF ．∴AF=BC ．∵在Rt △AFE 和Rt △BCA 中，AF=BC ，AE=BA ，∴△AFE ≌△BCA （HL ）．∴AC=EF ．（2）∵△ACD 是等边三角形，∴∠DAC=60°，AC=AD ．∴∠DAB=∠DAC+∠BAC=90°．∴EF ∥AD ．∵AC=EF ，AC=AD ，∴EF=AD ．∴四边形ADFE是平行四边形．考点：1．全等三角形的判定与性质；2．等边三角形的性质；3．平行四边形的判定．22．（1）y1＝273x-+;y2＝13x2﹣4x+2；（2）5月出售每千克收益最大，最大为73．【解析】【分析】（1）观察图象找出点的坐标，利用待定系数法即可求出y1和y2的解析式；（2）由收益W=y1-y2列出W与x的函数关系式，利用配方求出二次函数的最大值．【详解】解：（1）设y1＝kx+b，将（3，5）和（6，3）代入得，3563k bk b+=⎧⎨+=⎩，解得237kb⎧=-⎪⎨⎪=⎩．∴y1＝﹣23x+1．设y2＝a（x﹣6）2+1，把（3，4）代入得，4＝a（3﹣6）2+1，解得a＝13．∴y2＝13（x﹣6）2+1，即y2＝13x2﹣4x+2．（2）收益W＝y1﹣y2，＝﹣23x+1﹣（13x2﹣4x+2）＝﹣13（x﹣5）2+73，∵a＝﹣13＜0，∴当x＝5时，W最大值＝73．故5月出售每千克收益最大，最大为73元．【点睛】本题考查了一次函数和二次函数的应用，熟练掌握待定系数法求解析式是解题关键，掌握配方法是求二次函数最大值常用的方法23．（1）y=12x2+x﹣32（2）存在，（﹣1﹣，2）或（﹣，2）（3）点F的坐标为（﹣1，2）、（3，﹣2）、（﹣5，﹣2），且平行四边形的面积为 1 【解析】【分析】（1）设抛物线解析式为y=ax2+bx+c，把（﹣3，0），（1，0），（0，32）代入求出a、b、c的值即可；（2）根据抛物线解析式可知顶点P的坐标，由两个三角形的底相同可得要使两个三角形面积相等则高相等，根据P点坐标可知E点纵坐标，代入解析式求出x的值即可；（3）分别讨论AB为边、AB为对角线两种情况求出F点坐标并求出面积即可；【详解】（1）设抛物线解析式为y=ax2+bx+c，将（﹣3，0），（1，0），（0，32）代入抛物线解析式得09a-3b+c0a+b+c32c⎧⎪=⎪=⎨⎪⎪=-⎩，解得：a=12，b=1，c=﹣32∴抛物线解析式：y=12x2+x﹣32（2）存在．∵y=12x2+x﹣32=12（x+1）2﹣2∴P点坐标为（﹣1，﹣2）∵△ABP的面积等于△ABE的面积，∴点E到AB的距离等于2，设E（a，2），∴12a2+a﹣32=2解得a1=﹣1﹣22，a2=﹣1+22∴符合条件的点E的坐标为（﹣1﹣22，2）或（﹣1+22，2）（3）∵点A（﹣3，0），点B（1，0），∴AB=4若AB为边，且以A、B、P、F为顶点的四边形为平行四边形∴AB∥PF，AB=PF=4∵点P坐标（﹣1，﹣2）∴点F坐标为（3，﹣2），（﹣5，﹣2）∴平行四边形的面积=4×2=1若AB为对角线，以A、B、P、F为顶点的四边形为平行四边形∴AB与PF互相平分设点F（x，y）且点A（﹣3，0），点B（1，0），点P（﹣1，﹣2）∴3112200222xy-+-+⎧=⎪⎪⎨+-+⎪=⎪⎩，∴x=﹣1，y=2∴点F（﹣1，2）∴平行四边形的面积=12×4×4=1综上所述：点F的坐标为（﹣1，2）、（3，﹣2）、（﹣5，﹣2），且平行四边形的面积为1．【点睛】本题考查待定系数法求二次函数解析式及二次函数的几何应用，分类讨论并熟练掌握数形结合的数学思想方法是解题关键.24．证明见解析【解析】【详解】∵四边形ABCD是平行四边形，∴AD//BC，AD=BC，∵AE=CF∴AD-AE=BC-CF即DE=BF∴四边形BFDE是平行四边形.25．（1）此人所在P的铅直高度约为14.3米；（2）从P到点B的路程约为17.1米【解析】分析：(1)过P作PF⊥BD于F，作PE⊥AB于E，设PF＝5x，在Rt△ABC中求出AB，用含x的式子表示出AE，EP，由tan∠APE，求得x即可；(2)在Rt△CPF中，求出CP的长.详解：过P作PF⊥BD于F，作PE⊥AB于E，∵斜坡的坡度i＝5:1，设PF＝5x，CF＝1x，∵四边形BFPE为矩形，∴BF＝PEPF＝BE.在RT△ABC中，BC＝90，tan∠ACB＝AB BC，∴AB＝tan63.4°×BC≈2×90＝180，∴AE＝AB－BE＝AB－PF＝180－5x，EP＝BC＋CF≈90＋10x.在RT△AEP中，tan∠APE＝1805490123 AE xEP x-≈＝＋，∴x＝207，∴PF＝5x＝10014.3 7≈.答：此人所在P的铅直高度约为14.3米.由(1)得CP＝13x，∴CP＝13×207≈37.1，BC＋CP＝90＋37.1＝17.1.答：从P到点B的路程约为17.1米.点睛：本题考查了解直角三角形的应用，关键是正确的画出与实际问题相符合的几何图形，找出图形中的相关线段或角的实际意义及所要解决的问题，构造直角三角形，用勾股定理或三角函数求相应的线段长. 26．见解析【解析】【分析】根据等腰三角形的性质与判定及线段垂直平分线的性质解答即可.【详解】过点A作AH⊥BC，垂足为H．∵在△ADE中，AD=AE（已知），AH⊥BC（所作），∴DH=EH（等腰三角形底边上的高也是底边上的中线）．又∵BD=CE（已知），∴BD+DH=CE+EH（等式的性质），即：BH=CH．∵AH⊥BC（所作），∴AH为线段BC的垂直平分线．∴AB=AC（线段垂直平分线上的点到线段两个端点的距离相等）．∴∠B=∠C（等边对等角）．【点睛】本题考查等腰三角形的性质及线段垂直平分线的性质，等腰三角形的底边中线、底边上的高、顶角的角平分线三线合一；线段垂直平分线上的点到线段两端的距离相等；27．（1）4，5；（2）①7；②4或12-或12+8.【解析】【分析】()1分别令y 0=可得b 和m 的值；()2①根据ACP V 的面积公式列等式可得t 的值；②存在，分三种情况：i)当AC CP =时，如图1，ii)当AC AP =时，如图2，iii)当AP PC =时，如图3，分别求t 的值即可．【详解】()1把点()C 2,m 代入直线y x 2=+中得：m 224=+=，∴点()C 2,4，Q 直线1y x b 2=-+过点C ， 142b 2=-⨯+，b 5=； ()2①由题意得：PD t =，y x 2=+中，当y 0=时，x 20+=，x 2=-，()A 2,0∴-，1y x 52=-+中，当y 0=时，1x 502-+=， x 10=，()D 10,0∴，AD 10212∴=+=，ACP QV 的面积为10，()112t 4102∴-⋅=， t 7=，则t 的值7秒；②存在，分三种情况：i)当AC CP =时，如图1，过C 作CE AD ⊥于E ，PE AE 4∴==，PD 1284∴=-=，即t 4=；ii)当AC AP =时，如图2，2212AC AP AP 4442===+=，1DP t 1242∴==-，2DP t 1242==+；iii)当AP PC =时，如图3，OA OB 2==Q ，BAO 45∠∴=o ，CAP ACP 45∠∠∴==o ，APC 90∠∴=o ，AP PC 4∴==，PD 1248∴=-=，即t 8=；综上，当t 4=秒或(12-秒或(12+秒或8秒时，ACP V 为等腰三角形．【点睛】本题属于一次函数综合题，涉及的知识有：待定系数法求一次函数解析式，坐标与图形性质，勾股定理，等腰三角形的判定，以及一次函数与坐标轴的交点，熟练掌握性质及定理是解本题的关键，并注意运用分类讨论的思想解决问题．。

2019-2020学年湛江二中港城中学高三英语下学期期中试题及答案解析

2019-2020学年湛江二中港城中学高三英语下学期期中试题及答案解析

2019-2020学年湛江二中港城中学高三英语下学期期中试题及答案解析第一部分阅读（共两节，满分40分）第一节（共15小题；每小题2分，满分30分）阅读下列短文，从每题所给的A、B、C、D四个选项中选出最佳选项AExciting Adventure Options to Choose From!BIRD WALK(Any time of year)-Join us for a private bird walk through our sanctuary(保护区）。

The Bent's grasslands, trees and woods provide great habitat(栖息地）for birds moving from one place to another, such as Warblers, Vireos, Indigo Buntings, Thrushes, Orioles, and more. This walk will be made to the members in your party.Suitable for ages 5 and upProgram Fee:$150NATURE HIKE(Any time of year)-Take a private hike with Bent of the River! Your personal guide will show you notable habitats and wildlife around the center trails. Nature is exciting and always changing, so you never know what we will find along the way! This program is ideal for people who want to enjoy beautiful scenery while hiking.Suitable for ages 8 and upProgram Fee:$150POMPERAUG RIVER EXPLORATION(June and July only)-Many fascinating creatures live in and around the Pomperaug River! During this recreational(休闲的)program, an Audubon naturalist will share the human and natural history of the river and teach you how to catch fish and animals. The Bent will supply you with necessary tools, such as nets, containers, and field guides. Once the animals are caught, we will observe and identify(确定身份)them and learn how they can help show the health of the river before we put them back to the wild.Suitable for ages 8 and upProgram Fee:$150OWL PROWL(January and February only)-Enjoy a special guided adventure in search of one of the most beloved groups of birds-owls(猫头鹰）！We will be prowling for owls on awalk through the grassland and forests in hopes of seeing one of the three owl species known to live in Connecticut: the Great-horned Owl, Barred Owl, or Eastern Screech-Owl.Evening eventSuitable for ages 10 and upProgram Fee:$2251.Which of the programs is suitable for the Browns with a girl of five years old?A.BIRD WALK.B.NATURE HIKE.C.POMPERAUG RIVER EXPLORATION.D.OWL PROWL.2.What will you do with the fish you catch in POMPERAUG RIVER EXPLORATION?A.Find out their health.B.Do a scientific research.C.Cook them as food on the table.D.Set them free back to the river.3.Whom is this text written for?A.Students.B.Teachers.C.Scientists.D.Adventurers.BWhere doyou usually put your toothbrush?Do you keep it in the bathroom? How’s your toothbrush looking these days? Even if you can’t see it with a naked eye, experts say it may be saturated(使饱和)with millions of toilet germs!Dr. Charles Oerba, a germ expert, is amicrobiology professor at the University of Arizona. He says there are approximately 3 million bacteria per square inch in most toilet bowls, and every time you flush it without closing the lid, those millions of bacteria droplets spray into the air as far as twenty feet away and dirty everything in their path. And a common victim is your poor toothbrush, usually, left out on the bathroom sink, right?So, what do we do? Dr. Gerba says it’s easy. Close the toilet lid before you flush—that’ll greatly cut downthe germs, which will otherwise float in the air. And wash your toothbrush every few days in mouthwash or peroxide to get rid of any germs hiding in it. You can even put it through the dishwasher to sanitize(消毒)it. And always store your toothbrush in a closed cabinet.Here’s one more tip from Dr. Gerba, who says our kitchen sink is probably dirtier than our toilet. “If an alien came from space and studied the bacterial counts, he probably would conclude he should wash his hands in your toilet and go to the bathroom in your sink.” He says that’s because the kitchen sink is a great place where E. coli(大肠杆菌)to live and grow since it’s wet and damp. Bacteria feed on the food that people put down the drain or—that’s left on dishes in the sink. To reset your sink’s bacteria count back to zero, you’d better regularly wash it with hot water and sanitize yoursink with special chemicals. In fact, you may want to do it every day or before preparing dinner.4. What is the purpose of the text?A. To show how to brush your teeth.B. To tell people the importance of health.C. To warn people of the invisible germs.D. To introduce a microbiology professor.5. What can we learn from Paragraph 2?A. Bathroom sinks are the dirtiest places.B. Bacteria are bad for people’s health.C. Why bacteria spread through the air.D. How bacteria spread in the bathroom.6. What does the underlined word“that”in Paragraph 4 refer to?A. The food.B. The toothbrush.C. The sink.D. The chemical.7. Why does Dr. Gerba mention the example of an alien?A. To tell us a fiction story of an alien studying bacteria.B. To show our kitchen sink may be dirtier than our toilet.C. To teach us how to reset sink’s bacteria count back to zero.D. To prove coli prefers to live in the kitchen and the drain.CHidden beneath the surface in the roots of Earths astonishing and diverse plant life, there exists a biological superhighway linking together the members of the plant kingdom in what researchers call the "wood wide web".The network is comprised of thin threads of fungus (真菌) that grow outwards underground up to a few meters from its partnering plant, meaning that all of the plant life within a region likely connected to one another. The partnership is beneficial for both parties involved, plants provide carbohydrates (碳水化合物) to the funguses and in exchange, the funguses aid in gathering water and providing nutrients to its partnering plant.A study conducted by Rensen Zeng of theSouthChinaAgriculturalUniversityfound that this also allowed for plants to warn one another of potential harm. The study showed Broad Beans used the fungal network to spy on one another for upcoming danger.Like our Internet, this fungal connectivity is also full of crime. Some plants, such as Golden Marigolds have been found to release poisons into the network to slow down the growth of surrounding plants in the fight forwater and light. Other plants, such as the Phantom Orchid, do not have the chlorophyll (叶绿素) and must get the necessary nutrients from surrounding plants.Research suggests that animals such as insects and worms may be able to detect slight exchanges of nutrients through the network, allowing them to more easily find delicious roots to feed on; however, this has not been conclusively made clear in experimentation. The more we learn about this phenomenon, the more our understanding of the plant life of our planet will continue to change. Perhaps one day, we may be able to map out these complex networks entirely.8. What is the function of the first paragraph?A.To explain the aim of the web.B. To introduce the main topic.C. To give definition of diverse life.D. To show the importance of plants.9. The criminal behavior of plants can be seen as a way to________.A. compete for survivalB. gather more waterC. take in sunlightD. break natural rules10. What does the last paragraph suggest?A. Animals can also feed on the fungus.B. Nutrient exchanges are too slight to detect.C. No experiment can prove the phenomenon.D. More needs to be done to work out the network.11. Which can be the best title for the text?A. The Partnership between PlantsB. The Unknown Roots of the EarthC. The Superhighway Linking the PlantsD. The Mysterious Map Changing the WorldDThe common use of Google Maps, a navigation(导航) app on smartphones, raises the age-old question we meet with any technology:What skills are we losing? But also, crucially: What capabilities are we gaining?People who are good at finding their way around or good at using paper maps usually experience lots of confusion with digital maps. For example, they may mess up the direction of north and south, and you can see only a small section at a time. But consider what digital navigation aids have meant for someone like me. Despite being a frequent traveler, I’m so terrible at finding my way that I still use Google Maps almost every day in the small town where I have lived for many years. What seems unnecessary to some has been a significant expansion of my own capabilities.Part of the problem is that reading paper maps requires a specific skill set. There is nothing natural about them. In many developed nations, street names and house numbers are meaningful, and instructions such as “go north for three blocks and then west” usually make sense. In Istanbul, in contrast, where I grew up, none of those hold true. For one thing, the locals rarely use street names, and house numbers often aren’tsequentialeither because after buildings 1, 2 and 3 were built, someone squeezed in another house between 1 and 2, and now that’s 4. But then 5 will maybe get built after 3, and 6 will be between 2 and 3. Besides, the city is full of winding and ancient streets that meet with newer ones. Therefore, instructions as simple as “go north” would require a helicopter. I got lost all the time.But since I used Google Maps, I travel with a lot more confidence, and my world has opened up. And because I go to more places more confidently, I believe my native navigation skills have somewhat improved, too.That brings me back to my original question: while we often lose some skills after seeking convenience from technology, this new setup may also allow us to expand our capabilities and do something more confidently. Maybe when technology closes a door, we should also look for the doors it opens.12. How does the author feel about Google Maps?A Confusing. B. Unnecessary. C. Complicated. D. Helpful.13. Which contributes to the difficulty of finding ways in Istanbul?A. Strange street names.B. Ordinary paper maps.C. Complex road arrangements.D. Lack of road instructions.14. What does the underlined word “sequential” in Paragraph 3 probably mean?A. In a fixed order.B. In good condition.C. Of great importance.D. Of the same kind.15. What column of a newspaper may this passage belong to?A. Fashion.B. Opinion.C. Society.D. Geography.第二节（共5小题；每小题2分，满分10分）阅读下面短文，从短文后的选项中选出可以填入空白处的最佳选项。

2019-2020学年湛江二中港城中学高三英语下学期期中考试试卷及答案解析

2019-2020学年湛江二中港城中学高三英语下学期期中考试试卷及答案解析

2019-2020学年湛江二中港城中学高三英语下学期期中考试试卷及答案解析第一部分阅读（共两节，满分40分）第一节（共15小题；每小题2分，满分30分）阅读下列短文，从每题所给的A、B、C、D四个选项中选出最佳选项AFour Best Cities to Visit in WinterCold rains, icy sidewalks and gray skies can make winter travel a trial. But here are four cities around the world that make for a great cold-weather destination:Prague,Czech RepublicWith its snow-capped spires and winding streets,Pragueis a fairytale city that remains ly tourist-free in winter.The amazing architecture looks even prettier under a sheet of snow, with one of the most beautiful areas being the old town, with its Romanesque vaults. Gas street lamps have been placed throughout the city center, adding a romantic color1 to evenings. Cafes here are ideal for escaping the bitter cold.Salzburg,AustriaWith its Christmas songs and traditional markets, this is a perfect city for a winter break. “Silent Night” was performed for the first time in thechurchofOberndorfon the border ofSalzburgon Christmas Eve in 1818.The city's main market is held in the shadow ofSalzburg'sHohensalzburgCastle, but the one held inMirabell Squareis especially popular with food lovers who come to taste local food such as halusky—pieces of dumpling mixed with fried bacon.Tromso,NorwayTromso is widely regarded asNorway's most beautiful city and is a base for spoiling the northern lights. There are several attractive museums, including thePolarMuseum, which offers an insight into the history of Arctic expeditions, and theTromsoMuseum, which is famous for its Sami exhibitions.Amsterdam,NetherlandsIn winter,Amsterdam' s museums are much less crowded, making it the time to visit attractions such as Rijksmuseum or the Anne Frank House. Built originally to house a circus, the Royal Carre Theater is more than 130 years old. Children will love the spectacular performances.1. What can you do inPrague?A. Enjoy the fascinating architecture.B. Taste local food halusky.C. Appreciate Sami exhibitions.D. Watch a circus performance.2. Where was “Silent Night” first performed?A. In thechurchofOberndorf.B. InHohensalzburgCastle.C. InMirabell Square.D. In the Polar Museum.3. Which city will you choose if you want to see the northern lights?A. Prague.B. Salzburg.C. Tromso.D.Amsterdam.BWe all use different ways to remember ideas, facts and things we need to store. Remembering is an extremely important part of our learning experience. Information process, storage and recall encourage purposeful learning.But the brain doesn’t store everything we want or need for future use. It makes choices and tends to remember information that forms a memorable pattern. Things you learned recently can be particularly difficult to remember because they haven’t taken root in your mind.“Forgetting allows us to remember what is really important to our survival. We forget much of what we read, watch, and think directly every day.” writes John Medina in his book, Brain Rules.How do you avoid losing 90%of what you’ve learned? An inspiring writer and speaker Zig Ziglar once said: “Repetition is the mother of learning, the father of action, which makes it the architect of accomplishment.”Repetition has been a remembering skill for ages. When you hear or read something once，you don’t really learn it-at least not well enough to store the new information for long. The right kind of repetition can do wonders for your memory. People learn or remember better by repeating things or getting exposed to information many times. Othersrepeat particular steps or processes deliberately a number of times or even years to become better at certain skills.Daniel Coyle explains in his book, The Little Book of Talent:“...closing the book and writing a summary, even short ones, forces you to figure out the key points, process and organize those ideas so they make sense, and write them on the page. When you pick it back up weeks later, reread all of your notes or highlights to strengthen the ideas even further.”People learn by repeating things. Better learning is a repetition process. Every time we repetitively access something we already know, we increase the memory’s stored value.4. Which of the following can be inferred from the passage?A. The brain tends to store 90% of the things we learn.B. The fresher the information isthe easier to remember.C. Thinking is more important than remembering in study.D. The brain tends to choose and keep what it thinks important.5. How does the writer prove his opinion?A.By giving examples.B. By listing numbers.C. By borrowing words of experts.D. By providing scientific finding.6. What does Daniel Coyle want to say in his book?A. You can’t pay too much attention to repetition.B. Summarizing is a very effective learning tool.C. Forgetting forces human brain to make choices.D. Regular repetition helps to form good habits.7. Which do you think is the best title of the passage?A. How the Brain WorksB. Reading for MoreC. Fighting Against ForgettingD. Repeat to RememberCDid you know that horses talk? Well, they do, and you can lean to understand “horse talk” if you pay close attention to the horses you see.When horses live in the wild, other animals try to eat them, so a lot of horse talk is about staying alive. Even now, when most horses live on farms, they watch for danger. For this reason, never walk behind a horse. If you surprise it, the horse might mistake you for a mountain lion or wolf and give a dangerous kick.By watching the ears of a horse, you can get clues to what it's hearing. A horse can tum each ear in a different direction. For a wild horse, this trick is important for survival. The horse can hear something sneaking up behind it while also checking out a threatening noise in front. When a horse lets its ears down, it's feeling safe and relaxed. If horses becomeisolated, they neigh, or “whinny,” calling for company. They're saying, “Where are you? I'm over here!” If a horse snorts(哼) while holding its head high and staring at something, it's saying, “That looks dangerous. Get ready to run!” When two horses meet, they put their noses together and smell each other's breath. It's their way of asking, “Are you a friend?” Horses nicker,too. Nickering is a quiet sort of sound. This friendly noise means they're feeling secure and saying, “Clad to see you.”In the wild, horses live in herds, with all members watching for danger. In a herd, only one horse is the leader, the “boss hoss”. The “boss hoss” is usually an older female. She watches for threats and teaches younger horseshow to behave. However, others may want her job. When that happens, she pins her ears back against her head and may even bite or kick to get challengers to back off. She's using body language to say, “Hey, I'm in charge here!” All horses know that the one who makes others move is the leader. Horses relate to people that way, too.Horses have a language of their own. Now you know a bit of what they might be saying.8. What is the general idea of this passage?A. Horses can talk with their owners.B. You can know a bit of horses' language.C. Horses can “talk” in their own way.D. Other animals can also learn language.9. What does the underlined word “isolated” in Paragraph 3 mean?A. Lonely.B. Glad.C. Sad.D. Frightened.10. What will a horse do when he wants to know whether another horse is a friend?A. He will let his ears down.B. He and another horse will put their noses together and smell each other's breath.C They both will hold their heads high and stare at something.D. He will give another horse a dangerous kick.11. How will the “boss hoss” deal with her challengers?A. By warning or fighting.B. By watching for threats.C. By teaching younger horses how to behave.D. By relating to people.DFirefighters in Florida this week helped rescue a bald eagle with a fishing hook stuck in its beak（嘴）and the attached line wrapped around its wing and beak. Firefighters at Pasco County Fire Rescue Station 21 on Thursday were greeted by two children holding the injured bald eagle and seeking help, according to the station’s Facebook page.The firefighters called Owl’s Nest Sanctuary（保护区）for Wildlife in Odessa for assistance and a volunteer came out to help. "It appears that the eagle was wrapped in the line for about two days, was underweight, and thirsty,” the post said.Floridahas one of the densest concentrations of nesting bald eagles in the lower 48 stateswith an estimated 1 ,500 nesting pairs according to the Florida Fish and Wildlife Conservation Commission.PascoCountyis located in the state's west central coast north ofTampa.After the eagle was examined, it was placed in a container and taken to the sanctuary for treatment where Kris Potter, the sanctuary's director, successfully removed the hook.The sanctuary posted on its Facebook page that the eagle is making up for lost time when it comes to food. "He's eating all his meals with great enthusiasm and doesn't leave a crumb（碎屑）behind,“ the post said. "In the meantime, this big guy is resting and recovering ——he's already looking so much better!”After the eagle is considered stable, it will be taken toBuschGardensinTampafor further treatment, according to the post.“ Thankfully the eagle appears in good health and veterinarians（兽医）believe that the eagle will fully recover," the post said.When the eagle is cleared for return to the wild, it will be released in the area around Station 21 , the station said in its post.“A big thank-you to everyone who helped save this bald eagle's life! We are thankful for this happy outcome!” the post concluded. The sanctuary used the story to remind those who enjoy fishing to properly dispose of their garbage.12. Who initially found the injured bald eagle?A. Firefighters.B. Two children.C. The sanctuary's founder.D. A volunteer.13. Where will the eagle be set free?A. AtPascoCounty Fire Rescue Station 21.B. In the neighborhood around Station 21.C. In the sanctuary inOdessa.D. InBuschGardensinTampa.14. Why did the sanctuary post the story?A. To win a good reputation.B. To praise those firefighters.C. To appeal to people to protect bald eagles.D. To remind fishing lovers to deal with rubbish properly.15. What can we know about the outcome of the event?A. It's unexpected.B. It's beautiful.C. It's humorous.D. It's discouraging.第二节（共5小题；每小题2分，满分10分）阅读下面短文，从短文后的选项中选出可以填入空白处的最佳选项。

广东省湛江市2019-2020学年第二次中考模拟考试数学试卷含解析

广东省湛江市2019-2020学年第二次中考模拟考试数学试卷含解析

广东省湛江市2019-2020学年第二次中考模拟考试数学试卷一、选择题（本大题共12个小题，每小题4分，共48分．在每小题给出的四个选项中，只有一项是符合题目要求的．） 1．下列图形中，是中心对称图形，但不是轴对称图形的是( )A ．B ．C ．D ．2．化简(﹣a 2)•a 5所得的结果是( ) A ．a 7B ．﹣a 7C ．a 10D ．﹣a 103．若x ，y 的值均扩大为原来的3倍，则下列分式的值保持不变的是（ ）A ．2x x y+-B ．22y xC ．3223y xD ．222()y x y - 4．如图所示，a ∥b ，直线a 与直线b 之间的距离是（ ）A ．线段PA 的长度B ．线段PB 的长度C ．线段PC 的长度D ．线段CD 的长度5．如图，下列图形都是由面积为1的正方形按一定的规律组成，其中，第（1）个图形中面积为1的正方形有2个，第（2）个图形中面积为1的正方形有5个，第（3）个图形中面积为1的正方形有9个，…，按此规律．则第（6）个图形中面积为1的正方形的个数为（ ）A ．20B ．27C ．35D ．406．下列各式中计算正确的是 A ．()222x y x y +=+B ．()236x x =C ．()2236x x = D ．224a a a +=7．许昌市2017年国内生产总值完成1915.5亿元，同比增长9.3%，增速居全省第一位，用科学记数法表示1915.5亿应为（ ） A ．1915.15×108B ．19.155×1010C．1.9155×1011D．1.9155×10128．若关于x的不等式组255332xxxx a+⎧>-⎪⎪⎨+⎪<+⎪⎩只有5个整数解，则a的取值范围()A．1162a-<-„B．116a2-<<-C．1162a-<-„D．1162a--剟9．每个人都应怀有对水的敬畏之心，从点滴做起，节水、爱水，保护我们生活的美好世界．某地近年来持续干旱，为倡导节约用水，该地采用了“阶梯水价”计费方法，具体方法：每户每月用水量不超过4吨的每吨2元；超过4吨而不超过6吨的，超出4吨的部分每吨4元；超过6吨的，超出6吨的部分每吨6元．该地一家庭记录了去年12个月的月用水量如下表，下列关于用水量的统计量不会发生改变的是（）用水量x（吨） 3 4 5 6 7频数 1 2 5 4﹣x xA．平均数、中位数B．众数、中位数C．平均数、方差D．众数、方差10．等式33=11x xxx--++成立的x的取值范围在数轴上可表示为（）A．B．C．D．11．实数a在数轴上对应点的位置如图所示，把a，﹣a，a2按照从小到大的顺序排列，正确的是（）A．﹣a＜a＜a2B．a＜﹣a＜a2C．﹣a＜a2＜a D．a＜a2＜﹣a12．一个正方体的平面展开图如图所示，将它折成正方体后“建”字对面是（）A．和B．谐C．凉D．山二、填空题：（本大题共6个小题，每小题4分，共24分．）13．如图(1)，将一个正六边形各边延长，构成一个正六角星形AFBDCE，它的面积为1；取△ABC和△DEF各边中点，连接成正六角星形A1F1B1D1C1E1，如图(2)中阴影部分；取△A1B1C1和△D1E1F1各边中点，连接成正六角星形A2F2B2D2C2E2，如图(3)中阴影部分；如此下去…，则正六角星形A4F4B4D4C4E4的面积为_________________．14．计算（a 3）2÷（a 2）3的结果等于________ 15．已知1A n n =--，23B n n =---（3n ≥），请用计算器计算当3n ≥时，A 、B 的若干个值，并由此归纳出当3n ≥时，A 、B 间的大小关系为______.16．已知关于x 的方程x 2＋mx ＋4＝0有两个相等的实数根，则实数m 的值是______． 17．如图，直线x=2与反比例函数2y x=和1y x =-的图象分别交于A 、B 两点，若点P 是y 轴上任意一点，则△PAB 的面积是_____．18．如图，在等腰△ABC 中，AB=AC ，BC 边上的高AD=6cm ，腰AB 上的高CE=8cm ，则BC=_____cm三、解答题：（本大题共9个小题，共78分，解答应写出文字说明、证明过程或演算步骤．19．（6分）在如图的正方形网格中，每一个小正方形的边长均为 1．格点三角形 ABC （顶点是网格线交点的三角形）的顶点 A 、C 的坐标分别是（﹣2，0），（﹣3，3）． （1）请在图中的网格平面内建立平面直角坐标系，写出点 B 的坐标；（2）把△ABC 绕坐标原点 O 顺时针旋转 90°得到△A 1B 1C 1，画出△A 1B 1C 1，写出点 B 1的坐标；（3）以坐标原点 O 为位似中心，相似比为 2，把△A1B1C1 放大为原来的 2 倍，得到△A 2B 2C 2 画出△A 2B 2C 2，使它与△AB 1C 1 在位似中心的同侧；请在 x 轴上求作一点 P ，使△PBB1 的周长最小，并写出点 P 的坐标．20．（6分）小张骑自行车匀速从甲地到乙地，在途中因故停留了一段时间后，仍按原速骑行，小李骑摩托车比小张晚出发一段时间，以800米/分的速度匀速从乙地到甲地，两人距离乙地的路程y （米）与小张出发后的时间x （分）之间的函数图象如图所示．求小张骑自行车的速度；求小张停留后再出发时y 与x 之间的函数表达式；求小张与小李相遇时x 的值．21．（6分）如图，在平面直角坐标系中有三点（1，2），（3，1），（-2，-1），其中有两点同时在反比例函数ky x=的图象上，将这两点分别记为A ，B ，另一点记为C ， （1）求出k 的值；（2）求直线AB 对应的一次函数的表达式；（3）设点C 关于直线AB 的对称点为D ，P 是x 轴上的一个动点，直接写出PC ＋PD 的最小值（不必说明理由）．22．（8分）如图，在平面直角坐标系xOy 中，直线16y k x =+与函数()20k y x x=>的图象的两个交点分别为A （1，5），B ． （1）求1k ，2k 的值；（2）过点P （n ，0）作x 轴的垂线，与直线16y k x =+和函数()20k y x x=>的图象的交点分别为点M ，N ，当点M 在点N 下方时，写出n 的取值范围．23．（8分）图1所示的遮阳伞，伞柄垂直于水平地面，其示意图如图2、当伞收紧时，点P 与点A 重合；当伞慢慢撑开时，动点P 由A 向B 移动；当点P 到达点B 时，伞张得最开、已知伞在撑开的过程中，总有PM=PN=CM=CN=6.0分米，CE=CF=18.0分米，BC=2.0分米、设AP=x 分米． （1）求x 的取值范围；（2）若∠CPN=60°，求x 的值；（3）设阳光直射下，伞下的阴影（假定为圆面）面积为y ，求y 关于x 的关系式（结果保留π）．24．（10分）如图，已知反比例函数y ＝kx的图象与一次函数y ＝x+b 的图象交于点A(1，4)，点B(﹣4，n)．求n 和b 的值；求△OAB 的面积；直接写出一次函数值大于反比例函数值的自变量x 的取值范围．25．（10分） 某居民小区一处圆柱形的输水管道破裂，维修人员为更换管道，需确定管道圆形截面的半径，如图是水平放置的破裂管道有水部分的截面．(1)请你用直尺和圆规作出这个输水管道的圆形截面的圆心(保留作图痕迹)；(2)若这个输水管道有水部分的水面宽AB ＝8 cm ，水面最深地方的高度为2 cm ，求这个圆形截面的半径．26．（12分）如图1，点P是平面直角坐标系中第二象限内的一点，过点P作PA⊥y轴于点A，点P 绕点A顺时针旋转60°得到点P'，我们称点P'是点P的“旋转对应点”．（1）若点P（﹣4，2），则点P的“旋转对应点”P'的坐标为；若点P的“旋转对应点”P'的坐标为（﹣5，16）则点P的坐标为；若点P（a，b），则点P的“旋转对应点”P'的坐标为；（2）如图2，点Q是线段AP'上的一点（不与A、P'重合），点Q的“旋转对应点”是点Q'，连接PP'、QQ'，求证：PP'∥QQ'；（3）点P与它的“旋转对应点”P'的连线所在的直线经过点（3，6），求直线PP'与x轴的交点坐标．27．（12分）某中学课外活动小组准备围建一个矩形生物苗圃园，其中一边靠墙，另外三边用长为30米的篱笆围成．已知墙长为18米(如图所示)，设这个苗圃园垂直于墙的一边的长为x米.若平行于墙的一边长为y米，直接写出y与x的函数关系式及其自变量x的取值范围.垂直于墙的一边的长为多少米时，这个苗圃园的面积最大，并求出这个最大值.参考答案一、选择题（本大题共12个小题，每小题4分，共48分．在每小题给出的四个选项中，只有一项是符合题目要求的．）1．A【解析】分析：根据中心对称图形的定义旋转180°后能够与原图形完全重合即是中心对称图形，以及轴对称图形的定义：如果一个图形沿一条直线折叠，直线两旁的部分能够互相重合，这个图形叫做轴对称图形，这条直线叫做对称轴，即可判断出答案．详解：A、此图形是中心对称图形，不是轴对称图形，故此选项正确；B、此图形不是中心对称图形，是轴对称图形，故此选项错误；C、此图形是中心对称图形，也是轴对称图形，故此选项错误；D 、此图形不是中心对称图形，是轴对称图形，故此选项错误． 故选A ．点睛：此题主要考查了中心对称图形与轴对称的定义，关键是找出图形的对称中心与对称轴． 2．B 【解析】分析:根据同底数幂的乘法计算即可,计算时注意确定符号. 详解: (-a 2)·a 5=-a 7. 故选B.点睛:本题考查了同底数幂的乘法，熟练掌握同底数的幂相乘，底数不变，指数相加是解答本题的关键. 3．D 【解析】 【分析】根据分式的基本性质，x ，y 的值均扩大为原来的3倍，求出每个式子的结果，看结果等于原式的即是答案． 【详解】根据分式的基本性质，可知若x ，y 的值均扩大为原来的3倍，A 、23233x x x y x y++≠--，错误；B 、22629y yx x≠，错误； C 、3322542273y y x x≠，错误； D 、()()22221829y y x y x y --＝，正确；故选D ． 【点睛】本题考查的是分式的基本性质，即分子分母同乘以一个不为0的数，分式的值不变．此题比较简单，但计算时一定要细心． 4．A 【解析】分析：从一条平行线上的任意一点到另一条直线作垂线，垂线段的长度叫两条平行线之间的距离，由此可得出答案.详解：∵a ∥b ，AP ⊥BC∴两平行直线a 、b 之间的距离是AP 的长度∴根据平行线间的距离相等∴直线a 与直线b 之间的距离AP 的长度 故选A.点睛：本题考查了平行线之间的距离，属于基础题，关键是掌握平行线之间距离的定义. 5．B 【解析】试题解析：第（1）个图形中面积为1的正方形有2个， 第（2）个图形中面积为1的图象有2+3=5个， 第（3）个图形中面积为1的正方形有2+3+4=9个， …， 按此规律，第n 个图形中面积为1的正方形有2+3+4+…+（n+1）=(3)2n n +个， 则第（6）个图形中面积为1的正方形的个数为2+3+4+5+6+7=27个． 故选B ．考点：规律型：图形变化类. 6．B 【解析】 【分析】根据完全平方公式对A 进行判断；根据幂的乘方与积的乘方对B 、C 进行判断；根据合并同类项对D 进行判断． 【详解】A. ()2222x y x xy y +=++，故错误. B. ()236x x =,正确.C. ()2239x x =，故错误. D. 2222a a a +=, 故错误. 故选B. 【点睛】考查完全平方公式，合并同类项，幂的乘方与积的乘方，熟练掌握它们的运算法则是解题的关键. 7．C 【解析】 【分析】科学记数法的表示形式为10n a ⨯的形式，其中110a ≤<，n 为整数．确定n 的值时，要看把原数变成a 时，小数点移动了多少位，n 的绝对值与小数点移动的位数相同．当原数绝对值>1时，n 是正数；当原数的绝对值<1时，n 是负数． 【详解】用科学记数法表示1915.5亿应为1.9155×1011， 故选C ． 【点睛】考查科学记数法，掌握绝对值大于1的数的表示方法是解题的关键. 8．A 【解析】 【分析】分别解两个不等式得到得x ＜20和x ＞3-2a ，由于不等式组只有5个整数解，则不等式组的解集为3-2a ＜x ＜20，且整数解为15、16、17、18、19，得到14≤3-2a ＜15，然后再解关于a 的不等式组即可． 【详解】255332x x x x a +⎧>-⎪⎪⎨+⎪<+⎪⎩①② 解①得x ＜20 解②得x ＞3-2a ，∵不等式组只有5个整数解， ∴不等式组的解集为3-2a ＜x ＜20， ∴14≤3-2a ＜15，1162a ∴-<-… 故选：A 【点睛】本题主要考查对不等式的性质，解一元一次不等式，一元一次不等式组的整数解等知识点的理解和掌握，能求出不等式14≤3-2a ＜15是解此题的关键． 9．B 【解析】 【分析】由频数分布表可知后两组的频数和为4，即可得知频数之和，结合前两组的频数知第6、7个数据的平均数，可得答案．【详解】∵6吨和7吨的频数之和为4-x+x=4，∴频数之和为1+2+5+4=12，则这组数据的中位数为第6、7个数据的平均数，即=5，∴对于不同的正整数x，中位数不会发生改变，∵后两组频数和等于4，小于5，∴对于不同的正整数x，众数不会发生改变，众数依然是5吨.故选B．【点睛】本题主要考查频数分布表及统计量的选择，由表中数据得出数据的总数是根本，熟练掌握平均数、中位数、众数的定义和计算方法是解题的关键．10．B【解析】【分析】根据二次根式有意义的条件即可求出x的范围．【详解】由题意可知：3010xx-≥⎧⎨+>⎩,解得：3x…,故选：B．【点睛】考查二次根式的意义，解题的关键是熟练运用二次根式有意义的条件.11．D【解析】【分析】根据实数a在数轴上的位置，判断a，﹣a，a2在数轴上的相对位置，根据数轴上右边的数大于左边的数进行判断.【详解】由数轴上的位置可得，a<0,-a>0, 0<a2<a,所以，a＜a2＜﹣a.故选D【点睛】本题考核知识点：考查了有理数的大小比较，解答本题的关键是根据数轴判断出a ，﹣a ，a 2的位置. 12．D【解析】分析：本题考查了正方体的平面展开图，对于正方体的平面展开图中相对的面一定相隔一个小正方形，据此作答．详解：对于正方体的平面展开图中相对的面一定相隔一个小正方形，由图形可知，与“建”字相对的字是“山”．故选：D ．点睛：注意正方体的空间图形，从相对面入手，分析及解答问题．二、填空题：（本大题共6个小题，每小题4分，共24分．）13．【解析】∵正六角星形A 2F 2B 2D 2C 2E 2边长是正六角星形A 1F 1B 1D 1C 1E 边长的12， ∴正六角星形A 2F 2B 2D 2C 2E 2面积是正六角星形A 1F 1B 1D 1C 1E 面积的14． 同理∵正六角星形A 4F 4B 4D 4C 4E 4边长是正六角星形A 1F 1B 1D 1C 1E 边长的116， ∴正六角星形A 4F 4B 4D 4C 4E 4面积是正六角星形A 1F 1B 1D 1C 1E 面积的1256． 14．1【解析】【分析】根据幂的乘方, 底数不变, 指数相乘; 同底数幂的除法, 底数不变, 指数相减进行计算即可.【详解】解：原式=6601a a a ÷==【点睛】本题主要考查幂的乘方和同底数幂的除法,熟记法则是解决本题的关键, 在计算中不要与其他法则相混淆. 幂的乘方, 底数不变,指数相乘; 同底数幂的除法, 底数不变, 指数相减.15．A B <【解析】试题分析：当n=3时，32，B=1，A ＜B ；当n=4时，A=23-≈0.2679，21≈0.4142，A ＜B ；当n=5时，52≈0.2631，32≈0.3178，A ＜B ；当n=6时，，B=2≈0.2679，A ＜B ；……以此类推，随着n 的增大，a 在不断变小，而b 的变化比a 慢两个数，所以可知当n≥3时，A 、B 的关系始终是A ＜B.16．±4【解析】分析：由方程有两个相等的实数根，得到根的判别式等于0，列出关于m 的方程，求出方程的解即可得到m 的值．详解：∵方程240x mx ++=有两个相等的实数根，∴2244140b ac m =-=-⨯⨯=V ，解得： 4.m =±故答案为 4.±点睛：考查一元二次方程()200++=≠ax bx c a 根的判别式24b ac ∆=-， 当240b ac ∆=->时，方程有两个不相等的实数根.当240b ac ∆=-=时，方程有两个相等的实数根.当240b ac ∆=-<时，方程没有实数根.17．32． 【解析】【详解】解：∵把x=1分别代入2y x =、1y x =-，得y=1、y=12-， ∴A （1，1），B （1，1x -）．∴13AB 122⎛⎫=--= ⎪⎝⎭． ∵P 为y 轴上的任意一点，∴点P 到直线BC 的距离为1．∴△PAB 的面积1133AB 222222=⨯=⨯⨯=． 故答案为：32．18 【解析】【分析】根据三角形的面积公式求出ABBC＝34，根据等腰三角形的性质得到BD＝DC＝12BC，根据勾股定理列式计算即可．【详解】∵AD是BC边上的高，CE是AB边上的高，∴12AB•CE＝12BC•AD，∵AD＝6，CE＝8，∴ABBC＝34，∴22ABBC＝916，∵AB＝AC，AD⊥BC，∴BD＝DC＝12 BC，∵AB2−BD2＝AD2，∴AB2＝14BC2＋36，即916BC2＝14BC2＋36，解得：BC．．【点睛】本题考查的是等腰三角形的性质、勾股定理的应用和三角形面积公式的应用，根据三角形的面积公式求出腰与底的比是解题的关三、解答题：（本大题共9个小题，共78分，解答应写出文字说明、证明过程或演算步骤．19．（1）（﹣4，1）；（2）（1，4）；（3）见解析；（4）P（﹣3，0）．【解析】【分析】（1）先建立平面直角坐标系，再确定B的坐标；（2）根据旋转要求画出△A1B1C1，再写出点B1的坐标；（3）根据位似的要求，作出△A2B2C2；（4）作点B关于x轴的对称点B'，连接B'B1，交x轴于点P，则点P即为所求.【详解】解：（1）如图所示，点B的坐标为（﹣4，1）；（2）如图，△A 1B 1C 1即为所求，点B 1的坐标（1，4）；（3）如图，△A 2B 2C 2即为所求；（4）如图，作点B 关于x 轴的对称点B'，连接B'B 1，交x 轴于点P ，则点P 即为所求，P （﹣3，0）．【点睛】本题考核知识点：位似，轴对称，旋转. 解题关键点：理解位似，轴对称，旋转的意义.20．（1）300米/分；（2）y=﹣300x+3000；（3）7811分． 【解析】【分析】（1）由图象看出所需时间．再根据路程÷时间=速度算出小张骑自行车的速度．（2）根据由小张的速度可知：B （10，0），设出一次函数解析式，用待定系数法求解即可.（3）求出CD 的解析式，列出方程，求解即可.【详解】解：（1）由题意得：240012003004-=（米/分）， 答：小张骑自行车的速度是300米/分；（2）由小张的速度可知：B （10，0），设直线AB 的解析式为：y=kx+b ，把A （6，1200）和B （10，0）代入得：10061200,k b k b +=⎧⎨+=⎩解得：3003000,k b =-⎧⎨=⎩∴小张停留后再出发时y 与x 之间的函数表达式；3003000y x =-+；（3）小李骑摩托车所用的时间：24003,800= ∵C （6，0），D （9，2400），同理得：CD 的解析式为：y=800x ﹣4800，则80048003003000x x -=-+，7811x = 答：小张与小李相遇时x 的值是7811分．【点睛】考查一次函数的应用，考查学生观察图象的能力，熟练掌握待定系数法求一次函数解析式是解题的关键.21．（2）2；（2）y=x+2；（334【解析】【分析】（2）确定A 、B 、C 的坐标即可解决问题；（2）理由待定系数法即可解决问题；（3）作D 关于x 轴的对称点D′（0，-4），连接CD′交x 轴于P ，此时PC+PD 的值最小，最小值=CD′的长．【详解】解：（2）∵反比例函数y=k x的图象上的点横坐标与纵坐标的积相同， ∴A （2，2），B （-2，-2），C （3，2）∴k=2．（2）设直线AB 的解析式为y=mx+n ，则有221m n m n ++⎧⎨-+-⎩＝， 解得11m n ⎧⎨⎩＝＝， ∴直线AB 的解析式为y=x+2．（3）∵C 、D 关于直线AB 对称，∴D （0，4）作D 关于x 轴的对称点D′（0，-4），连接CD′交x 轴于P ，此时PC+PD 的值最小，最小值=CD′=223+5=34．【点睛】本题考查反比例函数图象上的点的特征，一次函数的性质、反比例函数的性质、轴对称最短问题等知识，解题的关键是熟练掌握待定系数法确定函数解析式，学会利用轴对称解决最短问题．22．（1）11k =-，25k =；（2）0＜n ＜1或者n ＞1．【解析】【分析】(1)利用待定系数法即可解决问题；(2)利用图象法即可解决问题；【详解】解：（1）∵A （1，1）在直线16y k x =+上，∴11k =-，∵A （1，1）在()20k y x x=>的图象上， ∴25k =．（2）观察图象可知，满足条件的n 的值为：0＜n ＜1或者n ＞1．【点睛】此题考查待定系数法求反比例函数与一次函数的解析式，解题关键在于利用数形结合的思想求解. 23．（1）0≤x≤10；（1）x=6；（3）y=﹣94πx 1+54πx ．【解析】【分析】（1）根据题意，得AC=CN+PN，进一步求得AB的长，即可求得x的取值范围；（1）根据等边三角形的判定和性质即可求解；（3）连接MN、EF，分别交AC于B、H．此题根据菱形CMPN的性质求得MB的长，再根据相似三角形的对应边的比相等，求得圆的半径即可．【详解】（1）∵BC=1分米，AC=CN+PN=11分米，∴AB=AC﹣BC=10分米，∴x的取值范围是：0≤x≤10；（1）∵CN=PN，∠CPN=60°，∴△PCN是等边三角形，∴CP=6分米，∴AP=AC﹣PC=6分米，即当∠CPN=60°时，x=6；（3）连接MN、EF，分别交AC于B、H，∵PM=PN=CM=CN，∴四边形PNCM是菱形，∴MN与PC互相垂直平分，AC是∠ECF的平分线，PB=PC12x22-==6-1x2，在Rt△MBP中，PM=6分米，∴MB1=PM1﹣PB1=61﹣（6﹣12x）1=6x﹣14x1．∵CE=CF，AC是∠ECF的平分线，∴EH=HF，EF⊥AC，∵∠ECH=∠MCB，∠EHC=∠MBC=90°，∴△CMB∽△CEH，∴MBEH=CMCE，∴2226()18 MBEH=，∴EH1=9•MB1=9•（6x﹣14x1），∴y=π•EH1=9π（6x﹣14x1），即y=﹣94πx1+54πx．【点睛】此题主要考查了相似三角形的应用以及菱形的性质和二次函数的应用，难点是第（3）问，熟练运用菱形的性质、相似三角形的性质和二次函数的实际应用．24．（1）-1；（2）52；（3）x＞1或﹣4＜x＜0.【解析】【分析】（1）把A点坐标分别代入反比例函数与一次函数解析式，求出k和b的值，把B点坐标代入反比例函数解析式求出n的值即可；（2）设直线y＝x+3与y轴的交点为C，由S△AOB=S△AOC+S△BOC，根据A、B两点坐标及C点坐标，利用三角形面积公式即可得答案；（3）利用函数图像，根据A、B两点坐标即可得答案.【详解】（1）把A点（1，4）分别代入反比例函数y＝kx，一次函数y＝x+b，得k＝1×4，1+b＝4，解得k＝4，b＝3，∵点B（﹣4，n）也在反比例函数y＝4x的图象上，∴n＝44＝﹣1；（2）如图，设直线y＝x+3与y轴的交点为C，∵当x＝0时，y＝3，∴C（0，3），∴S△AOB＝S△AOC+S△BOC＝12×3×1+12×3×4＝7.5，（3）∵B（﹣4，﹣1），A（1，4），∴根据图象可知：当x＞1或﹣4＜x＜0时，一次函数值大于反比例函数值．【点睛】本题主要考查了待定系数法求反比例函数与一次函数的解析式和反比例函数y ＝k x中k 的几何意义，这里体现了数形结合的思想．25．（1）详见解析；（2）这个圆形截面的半径是5 cm.【解析】【分析】（1）根据尺规作图的步骤和方法做出图即可；（2）先过圆心O 作半径CO AB ，交AB 于点D ，设半径为r ，得出AD 、OD 的长，在Rt AOD △中，根据勾股定理求出这个圆形截面的半径.【详解】(1)如图，作线段AB 的垂直平分线l ，与弧AB 交于点C ，作线段AC 的垂直平分线l′与直线l 交于点O ，点O 即为所求作的圆心．(2)如图，过圆心O 作半径CO ⊥AB ，交AB 于点D ，设半径为r ，则AD ＝AB ＝4，OD ＝r －2，在Rt △AOD 中，r 2＝42＋(r －2)2，解得r ＝5，答：这个圆形截面的半径是5 cm.【点睛】此题考查了垂径定理和勾股定理，关键是根据题意画出图形，再根据勾股定理进行求解.26．（1）（﹣2，3，（﹣10，16﹣3，（2a ，b ﹣32a ）；（2）见解析；（3）直线PP'与x 轴的交3，0）【解析】【分析】（1）①当P （-4，2）时，OA=2，PA=4，由旋转知，∠P'AH=30°，进而P'H=12P'A=2，33，即可得出结论；②当P'（-5，16）时，确定出P'A=10，3PA=PA'=10，3得出结论；③当P （a ，b ）时，同①的方法得，即可得出结论；（2）先判断出∠BQQ'=60°，进而得出∠PAP'=∠PP'A=60°，即可得出∠P'QQ'=∠PAP'=60°，即可得出结论；（3）先确定出y PP '=3x+3，即可得出结论．【详解】解:（1）如图1，①当P （﹣4，2）时，∵PA ⊥y 轴，∴∠PAH=90°，OA=2，PA=4，由旋转知，P'A=4，∠PAP'=60°，∴∠P'AH=30°，在Rt △P'AH 中，P'H=12P'A=2， ∴33∴3，∴P'（﹣2，3，②当P'（﹣5，16）时，在Rt △P'AH 中，∠P'AH=30°，P'H=5，∴P'A=10，3，由旋转知，PA=PA'=10，OA=OH ﹣AH=16﹣3∴P （﹣10，16﹣3，③当P （a ，b ）时，同①的方法得，P'（a 2，b ﹣32a ）， 故答案为：（﹣2，3），（﹣10，16﹣3，（2a ，b ﹣32a ）； （2）如图2，过点Q 作QB ⊥y 轴于B ，∴∠BQQ'=60°，由题意知，△PAP'是等边三角形，∴∠PAP'=∠PP'A=60°，∵QB⊥y轴，PA⊥y轴，∴QB∥PA，∴∠P'QQ'=∠PAP'=60°，∴∠P'QQ'=60°=∠PP'A，∴PP'∥QQ'；（3）设y PP'=kx+b'，由题意知，k=3，∵直线经过点（3，6），∴b'=3，∴y PP'=3x+3，令y=0，∴x=3∴直线PP'与x30）．【点睛】此题是几何变换综合题，主要考查了含30度角的直角三角形的性质，旋转的性质，等边三角形的判定和性质，待定系数法，解本题的关键是理解新定义．27．112.1【解析】试题分析：（1）根据题意即可求得y与x的函数关系式为y=30﹣2x与自变量x的取值范围为6≤x＜11；（2）设矩形苗圃园的面积为S，由S=xy，即可求得S与x的函数关系式，根据二次函数的最值问题，即可求得这个苗圃园的面积最大值．试题解析：解：（1）y=30﹣2x（6≤x＜11）．（2）设矩形苗圃园的面积为S，则S=xy=x（30﹣2x）=﹣2x2+30x，∴S=﹣2（x﹣7.1）2+112.1，由（1）知，6≤x＜11，∴当x=7.1时，S最大值=112.1，即当矩形苗圃园垂直于墙的一边的长为7.1米时，这个苗圃园的面积最大，这个最大值为112.1．点睛：此题考查了二次函数的实际应用问题．解题的关键是根据题意构建二次函数模型，然后根据二次函数的性质求解即可．。

2019-2020学年湛江二中港城中学高三英语期中试题及答案解析

2019-2020学年湛江二中港城中学高三英语期中试题及答案解析

2019-2020学年湛江二中港城中学高三英语期中试题及答案解析第一部分阅读（共两节，满分40分）第一节（共15小题；每小题2分，满分30分）阅读下列短文，从每题所给的A、B、C、D四个选项中选出最佳选项AInformation on school visits to Kew GardensEnjoy yourselves in a wonderland of science with over 50,000 living plants and a variety of educational events or amusing activities. Here is essential information about planning a school visit to Kew.Educational course pricesYou can plan a self-led visit or book one of our educational courses. Students will take part in the educational courses in groups of 15. Prices vary according to different situations.EYFS (Early Years Foundation Stage) to Key Stage 4:45-minute course: 35/group 90-minute course: 70/groupKey Stage 5:Half day (one course): 80/group Full day (two courses): 160/groupTeachers and adults:Up to required key stage proportions (比例): FreeAdults needed for 1:1 special educational needs support: FreeAdults above the required proportions: 11/personThe payment will due within 28 calendar days of making the booking.Health and safetyRequired supervising (监护) adult-student proportions:Key Stage 1: 1:5 Key Stage 2: 1:8Key stage 3: 1:10 Key Stage 4: 1:12Key Stage 5: 1:12The group sizes should be controlled if you are visiting potentially busy areas such as the glasshouse and other attractions. The maximum number of students visiting the glasshouses is 15 per group and each group to Kew shops should include no more than 10 students.If there is an emergency, please contact the nearest Kew staff member or call Constabulary on 0208 32 3333 for direct and quick support. Please do not call 999.Planning your visitYour tickets and two planning passes will be sent to you upon receipt of your payment. You can complete your risk assessment with the passes, ensure you bring your tickets and the receipt document and show them to the staff members at the gate on the day of your visit.Recommended timingsThe Kew Gardens opens at 10 am. You are recommended to spend at least three to five hours on your visit. The closing time varies throughout the year. But the earliest is 3:30 pm. We have a fixed schedule for educational courses, which is from 10:30 am to 2:20 pm.1.How much should a group of 15 Key Stage I students and 4 teachers pay for a 45-minute course?A.35B.46C.57D.812.What should one do in an emergency?A.Check the risk assessment.B.Call 999 immediately.C.Ask adults or teachers for help.D.Seek help from the staff member nearby.3.What is the purpose of the text?A.To introduce Kew Gardens.B.To give tips on visiting Kew Gardens.C.To attract potential visitors to Kew Gardens.D.To inform coming activities in Kew Gardens.BMost children who have suffered from ADHD still have it as teens. During teen years, especially as the hormonal changes of teenagers are going on and the demands of school and extra-curricular activities are increasing, ADHD may get worse.Because of problems with getting unfocused and poor concentration, many teens with ADHD have problems in school. Grades may fall, especially if the teen is not getting ADHD treatment. It’s not uncommon for teens with ADHD to forget their homework, lose textbooks, and become bored with their daily class work. Teens may become inattentive or extremely attentive, not waiting for their turn before blurting out answers. They may cut in on their teacher and classmates. Teens with ADHD may also befidgetyand find it hard to sit still in class.Often, teens with ADHD are so busy focusing on other things that they forget about the task at hand. This canbe seen especially with homework and athletic skills and in relationships with their schoolmates. This lack of attention to what they’re doing often leads to bad grades on tests and being passed over for sports teams, after-school activities, and learning teams. Kids with ADHD can be targets for bullying, too. But, not all children with ADHD have trouble getting along with others. If your child does, you can take measures to help improve their social skills and relationships.ADHD affects all parts of a teenager’s life. As a parent you should discover your teen’s troubles as early as possible. The earlier your child’s troubles are discovered, the more successful the following steps can be.4. What does the author plan to do in paragraph 1?A. To list the types of ADHD.B. To introduce the main topic.C. To show the author’s opinion.D. To explain the causes of ADHD.5. What does the underlined word “fidgety” probably mean in paragraph 2?A. Clever.B. Noisy.C. Restless.D. Lazy.6. What is the text mainly about?A. Ways to deal with ADHD.B. Effects of ADHD on teens.C. Teens’ school performances.D. Demands of school work.7. What may the following paragraph talk about?A. How parents can help a teen with ADHD.B. The importance of healthy peer relationships.C. How many children are suffering from ADHD. D. Different opinions about treating ADHD in teens.COne day when I was 5, my mother criticized me for not finishing my rice and I got angry. I wanted to play outside and not to be made to finish eating my old rice. In my angry motion to open the screen door (纱门) with my foot, I kicked back about a 12-inch part of the lower left hand corner of the new screen door. But I had no regret, for I was happy to be playing in the backyard with my toys.Today, I know if my child had done what I did, I would have criticized my child, and told him about how expensive this new screen door was, and I would have delivered a spanking (打屁股) for it. But my parents never said a word. They left the corner of the screen door pushed out, creating an opening, a crack in the defense against unwanted insects.For years, every time I saw that corner of the screen, it would remind me of my mistake from time to time. For years, I knew that everyone in my family would see that hole and remember who did it. For years, every time Isaw a fly buzzing in the kitchen, I would wonder if it came in through the hole that I had created with my angry foot. I would wonder if my family members were thinking the same thing, silently blaming me every time a flying insectentered our home, making life more terrible for us all. My parents taught me a valuable lesson, one that a spanking or stern (严厉的) words perhaps could not deliver. Their silent punishment for what I had done delivered a hundred stern messages to me. Aboveall, it has helped me become a more patient person and not burst out so easily.8. When the author damaged the door, his parents _______.A. scolded him for what he had doneB. left the door unrepairedC. told him how expensive it wasD. gave him a spanking9. How did the author feel every time he saw the damaged door?A. He felt ashamed of his uncontrolled anger at that time.B. He found that his family members no longer liked him.C. He found it destroyed the happy atmosphere at his home.D. He felt he had to work hard to make up for (弥补) the damage.10. The experience may cause the author _______.A. to hide his anger away from othersB. not to go against his parents’ willC. to have a better control of himselfD. not to make mistakes in the future11. What of the following is the main idea of this passage?A. Adults should ignore their children’s bad behavior.B. Parents shouldn’t educate their children.C. What is the best way to become a more patient person?D. Silent punishment may have a better effect on educating people.DChinese paleontologists (古生物学家) have determined that, about 47 million years ago, subtropical forests once existed on the high-altitude Qinghai-Tibet Plateau.The conclusion, which appears in a paper published on Tuesday, was drawn based on the large number of fossils found in theBaingoinBasinat an altitude of nearly 5,000 meters during the second comprehensive scientific expedition to the plateau.A joint team from theXishuangbannaTropicalBotanical Gardenconducted the research on the fossils. By combining the findings and models, the team recreated the climate and altitude that existed 47 million years ago, showing that the central plateau had an altitude of just 1,500 meters and an annual average temperature of 19℃, says Su Tao, a researcher from the tropical botanical garden and first author of the paper.“It was covered by thick forest and was rich in water and grass. It is fair tocall it the ‘ShangriLa’ of ancient times,” Su adds.The researchers have also found over 70 plant fossils, the majority of which are most closely related to plant life in today's subtropical or tropical regions.“This is enough to show that the central part of the now high-altitude, freezing Qinghai-Tibet Plateau had flourishing subtropical plants 47 million years ago,” Su says.The findings provide new evidence for the study of the evolutionary history of biodiversity and the evolution of the plateau's landscape, according to Zhou Zhekun, the paper's corresponding author and a researcher at the tropical botanical garden.Chinalaunched the second comprehensive scientific expedition to the Qinghai-Tibet Plateau in June 2017, 40 years after the first. Lasting up to 10 years, the expedition will conduct a series of studies focusing on the plateau's glaciers, its biodiversity and ecological changes, and will also monitor the changes in climate.12. How did the paper come to the conclusion?A. Through the observation of the Baingoin basin.B. Through the fossils found in scientific expedition.C. Through the drawing of a large number of fossils.D. Through the adventure on the Qinghai-Tibetan Plateau.13. What can be inferred according to Su Tao?A. The average altitude of the plateau was 1,500 meters.B. “Shangrila”means a place with abundant water and grass.C. The flourishing subtropical plants have covered the plateau.D. The fossils found by researchers are tropical or subtropical plants now.14. Where might the passage come from?A. The Times.B. The Wall Street Journal.C. Chinese National Geography.D. The Economist.15. What is the purpose of the passage?A. To instruct.B. To educate.C. To persuade.D. To inform.第二节（共5小题；每小题2分，满分10分）阅读下面短文，从短文后的选项中选出可以填入空白处的最佳选项。

2019-2020学年湛江二中港城中学高三英语下学期期中试题及答案

2019-2020学年湛江二中港城中学高三英语下学期期中试题及答案

2019-2020学年湛江二中港城中学高三英语下学期期中试题及答案第一部分阅读（共两节，满分40分）第一节（共15小题；每小题2分，满分30分）阅读下列短文，从每题所给的A、B、C、D四个选项中选出最佳选项AMy Biggest ChallengeAs a writer on an adventure sports magazine, I’dalways fought shy of doing the adventurous stuff myself, preferring instead to observe the experts from a safe distance and relay their experiences to readers in the form of written language. Thus, when I was challenged to take part in a mountain climb in aid of raising money for charity-and to write about it afterwards-I was unwilling, to say the least.I was lucky enough to have a brilliant climbing coach called Keith, who put me through my paces after my daily work. He gave me knowledge about everything from the importance of building muscle groups to how to avoid tiredness through nutrition. It quickly became apparent that the mechanics of climbing were more complex than I had imagined. There was the equipment and techniques I’d never even heard of, all of which would come in handy on the snow-capped peak I’d be climbing.Aware of the challenge, Keith made a detailed action plan and I forced myself to stick to it, doing a daily workout at the gym and going on hikes with a heavy pack. I perfected my technique on the climbing wall and even went to climb the mountains to get vital experience. My self-belief increased alongside my muscle power and I became confident about finishing the climb.All too soon I was on a plane to my destination. On that day, when I looked up at the mountain, I thought of abandoning it. But then I remembered all the hard work I’d done and how disappointed Keith would be if I gave up at the last minute-not to mention letting down the charity and the sense of failure I’d experience myself. With a deep breath I gathered my equipment and headed out into the sunshine to meet the rest of the group.And as I sit here now, tapping away on my laptop, I’m amazed at the details in which I can recall every second of the climb: the burning muscles, the tiredness, the minor problems along the way. Could I have been better prepared? Possibly. Would I be back for another go? Thankfully not. The feeling of being excited when I stood on top of the world is a never-to-be-repeated experience but one I will enjoy forever nevertheless.1. At the beginning of the activity, the author revealed his ______.A. disappointment in the coming adventure.B. expectation of writing about his experience.C. lack of enthusiasm for the challenge he’d been offered.D. curiosity about taking part in the mountain climb for charity.2. What did the author realise during his climb training?A. The knowledge about climbing was really confusing.B. The equipment was the key factor to reach the peak.C. Climbing was much more complicated than expected.D. Hard training was far more important than making plans.3. How did the author feel after he succeeded in climbing the mountain?A. He was relieved that he wouldn’t have to do it again.B. He was well satisfied that he had done his best for it.C. He was surprised that he had managed to complete it.D.He was regretful that it wasn’t as smooth as imagined.BAs summer approaches, many kids and teenagers may find that they have more time in hand. One great way to make use of the extra time is to go on an adventure and travel. Clearly, I am not a naturally adventurous person, but I have found that takingthe risk and challenging myself to explore and travel to unfamiliar places can be a very rewarding experience.Because I am usually quite busy during the school year, most of my travels take place during the summer. Over the past few summers, I have hiked in the Grand Canyon, explored Niagara Falls, and camped out in upstate New York. Although these experiences are varied, they are similar in that they instill (灌输) a sense of appreciation for nature and a more balanced view on life. When I hiked in the Grand Canyon, for example, I was in awe(敬畏) of the geological influences that shaped the canyon.Adventures, of course, are not limited to hiking. There are many other choices, such as camping, volunteering in a foreign environment and travelling to different countries. In my opinion, adventures are more enjoyable with family or a few friends. There is a sense of bonding that one only gets through spending time together in outdoor adventures. For example, when I was in Boy Scouts, I often went on weekend camping trips with my friends. When I came back from a Boy Scouts camping trip, I often was eager to go outside more and explore the parks and nature around me.Next fall, I will attend college. In the meantime though, I hope to make the most of my summer to explore and travel. Now, I am planning on hiking and camping out in Maine.When I visited Maine last fall, I was amazed by how beautiful it was and the tall trees and coasts that exist, and I really hope to enjoy the beauty of nature there this summer.4. We can learn from the first paragraph about the author?A. He is an adventurous person by natureB. He likes challenging himself by travellingC. He enjoys travelling with other adventurersD He needs others’ help when going on an adventure5. Which of the following can make people’s adventure more enjoyable according to the author？A. Going to different countries.B. Going to unfamiliar places.C. Travelling withtheir family or friends.D. Travelling to distant places by themselves.6. What will the author do this summer？A. Explore Niagara Falls.B. Hike in the Grand Canyons.C. Camp out in upstate New York.D. Hike and camp out in Maine.7. Who is probably the author?A. A high school student.B. A college student.C. A friendly guide.D. A warm-hearted teacher.CA teenager in Georgia will no longer have to walk 7 miles to work after school thanks to one woman’s act of kindness.Jayden Sutton, a high school senior, went on foot each day from school to his job at a restaurant and then back home. Sutton was determined to work and make enough money to eventually buy his own vehicle.Sutton said he’d leave school at 3:30 pm, then walk miles to his job at the restaurant. After his work, which usually lasted six to eight hours, he walked home, sometimes not arriving back until almost midnight.That all changed when Myers saw him walking down the road in the rain in December. “The young man was insistently in a rush walking to work, saying ‘I can’t be late,’” Myers said. “He begged me to give him a ride. I told him I could take him as far as I was going. I began to create small talk along the way. It wasrevealedto me that his name was Jayden, 12th grader, worked 40 hours a week, walked 5 miles to work immediately after school, got off at 10:30 pm at night and walked back home another 5 miles if co-workers didn’t offer a ride.”After dropping Sutton off, Myers said his heart and determination filled her with tears. “He was smiling in good spirits and that’s a child worth blessing,” she told Fox News. So, Myers shared Sutton’s story on theGoFundMe page, which raised more than $ 9, 000 from 186 donors.She surprised Sutton with a new car after she managed to convince the general manager to drop the price of the vehicle to meet the budget.8. Why did Sutton work so hard in his spare time?A. To gain working experience.B. To pay for his education.C. To own a car.D. To support his family.9. What difficulty did Sutton have in his work at the restaurant?A. He worked longer than other workers.B. His work was too tiring.C. His job was much less paid.D. He had to walk to work.10. What does the underlined word “revealed” in paragraph 4 mean?A. Known.B. Attached.C. Believed.D. Limited.11. What do we know about the money donated online?A. It could buy more than a new car.B. It was not enough to buy a new car.C. It was given to Myers to buy herself a new car.D It mainly came from a car sales manager.DIt is essential that students have a category of school-related activities they can participate in. These activities can range from activities during normal school hours to after-school activities. No matter the time, these activities should be available to every student, and at Victory Pioneers International Schools (V.P.I.S) it is encouraged that every student participate in at least one activity, educational and recreational.One of the primary reasons school activities are important at V.P.I.S. is because it gives students the exercise they might not normally receive. Most popularly, these types of activities include major sports such as football, basketball, baseball, tennis, track and field and soccer but also might include gymnasium games and other games.Activities during V.P.I.S. also make a good impression on colleges if students are planning to pursue more education. Colleges look for students who do not just go to school and go home after school. These activities range from participating in clubs and sports to volunteering after school at a recreation center or having a part-time job. If a college sees you maintained good grades while participating in these activities, it will be impressed.V.P.I.S. activities also allow students to be creative. Gifted-and-talented activities allow gifted students toparticipate in what they otherwise would never have experienced in the classroom. They are a great way to allow students to be creative. Additionally, participating in clubs such as drama that appeal to students’ interest also allows them to expand their knowledge and be creative.Students also can have their interests expanded by participating in activities. These activities could consist of anything, such as joining the Future Business Leaders, the school’s debate team and the chess team, to name a few. By participating in these activities, a student might realize he is interested in something he never knew he was interested in before.12. What can we learn about activities at V.P.I.S.?A. Not every student has access to them.B. Students are required to take part in them after school.C. They give students exercise that might not be got in other schools.D. Educational activities are more popular with the students.13. What benefits can the students get from the activities?A. They can get extra grades when applying for colleges.B. They will become more gifted and talented .C. They may expand their knowledge in drama.D. They may better know their own interests.14. Which of the following is a suitable title for the passage?A. The Benefits of V.P.I.S. ActivitiesB. School-related Activities at V.P.I.S.C. Colleges Need Creative StudentsD. Activities Make You Creative15. Where is the passage probably from?A. A scientific magazine.B. A college application guideline.C. A club introduction.D. The website of V.P.I.S.第二节（共5小题；每小题2分，满分10分）阅读下面短文，从短文后的选项中选出可以填入空白处的最佳选项。

2019-2020学年湛江二中港城中学高三英语下学期期中考试试题及答案

2019-2020学年湛江二中港城中学高三英语下学期期中考试试题及答案

2019-2020学年湛江二中港城中学高三英语下学期期中考试试题及答案第一部分阅读（共两节，满分40分）第一节（共15小题；每小题2分，满分30分）阅读下列短文，从每题所给的A、B、C、D四个选项中选出最佳选项AFour remarkable inventionsFor more than half a century, the Consumer Electronics Show(CES) has been the place for companies and inventors to display their newest and coolest gadgets.Here are our picks for some of the most interesting and creative inventions.The Sweet Little Rolling RobotSamsung has released Ballie, a tennis-sized robot that can follow you around the house, answer your questions, and entertain your pets. Since it's equipped with a camera, it can keep an eye on your home while you're away. It's like a smart assistant that goes wherever you do, rolling into your bedroom to ring your wake-up alarm, rolling to the kitchen to turn on the toaster and giving you the weather report as you brush your teeth.The Insoles to Pick Up Your PactAny runner knows the right shoes are key to your speed. But Nurvv insoles promise more than mere cushioning. The insoles transmit data to a coaching app, which offers information on your technique and performance. It measures your foot strike and assesses your injury risk. The app then generates personalized workouts to set targets and help you beat your best speeds. Half marathon, here you come!The No-Studio-Needed Yoga ClassCan't keep up your commitment to a yoga studio membership? The Yoganotch personal yoga assistant lets you drop into a virtual class any time you want. Follow along with a set series while 3-D sensors tell you whether you need to straighten your legs a bit more. The idea it that it improves your form while reducing the risk of injury.The Dau-Enhanced GrillWhile working by sight, smell and feel, a chef may appreciate Weber's new Smart Grilling Hub. It can monitor your pork and turkey while an app gives advice about cooking technique and safe temperatures.1. What can the Sweet Little Rolling Robot do?A. Feed your pets.B. Hay tennis with you.C. Take you wherever you want.D. Assist you to do your housework.2. Which of the following is suitable for a runner?A. Ballie.B. Nurvv.C. Yoganotch.D. Smart Grilling Hub.3. What do we know about the Weber’s invention?A. It uses virtual reality.B. It is convenient for cooking.C. It makes meals for you automatically.D. It helps you do well in your yoga exercises.BIn 2002, young Elon Musk tried unsuccessfully to buy Russian rockets to help him send mice to Mars and back. Afterwards, the youngmillionaire decided to build his own rockets.Musk went to Southern California and started hiring people to help bring his dream to life. In a very short time, and despite some failures, his company SpaceX launched Falcon 1, the first successful privately-built liquid fuel rocket, into Earth's orbit in 2008.As the first Falcon rocket began testing, development was already underway for the Falcon 9. This much larger rocket, which uses nine engines to lift heavy payloads（有效载荷）into orbit, is engineered to return to Earth, ready to be reused for another flight.For Musk, space is the final destination. To help people get there, his company Neuralink is developing devices that will link people's brains with computers. A similar device has been developed at the University of Utah. It consists of a chip（芯片）with 256 threads（线程）that is placed between a person's skin and brain. The threads attach directly to brain tissue（脑组织）.Patients who have the device are able to use only their minds to communicate with one another through computers.Neuralink's chips will have about 1,000 threads. A robot developed by the company will place up to ten chips under a person's skin. The chips will communicate without wires but with a tiny device that will be worn behind the person's ear. That device, in turn, will communicate with computers. The primary market for the technology will be for people that, because of injuries or birth defects, cannot control their hands and arms. With Neuralink^ product, they'll be able to mentally command a computer to type messages for them or carry out other tasks.4. According to this article, what was the first Falcon 1 able to do?A. Launch big satellites.B. Reach distant moons.C. Move around our planet.D. Study the universe.5. What does the article explain about Neuralink's chips?A. How they'll be set up.B. What safety features they'll have.C. How much money they'll earn.D. Where they'll be produced.6. According to this article, who is Neuralink going to market its product to first?A. Those who own great wealth.B. Those who are physically disabled.C. Those who travel internationally.D. Those who do research on plants.7. In which publication is this article most likely to appear?A. The Journal of Environmental Studies.B. Advances in Business and Technology.C. Digest of Fashion and Entertainment News,D. Consumer's Guide to Outdoor Recreation.CA cheap printed sensor could transmit wildfire warnings. Wildfires have recently destroyed regions across the world, and theirgravityis increasing. Hoping to reduce harm, researchersled by Yapei Wang, a Chinese chemist ofRenminUniversity, say they have developed an inexpensive sensor to detect such fires earlier with less effort.Current detection methods rely heavily on human watchfulness, which can delay an effective response. Most wildfires are reported by the general public, and other alerts come from routine foot patrols and watchtower observers. Passing planes and satellites also occasionally spot something, but “the fire first appears on the ground," Wang says. “ When you see the fire from the sky, it is too late. ”The team says its new sensor can be placed near tree trunks' bases and send a wireless signal to a nearby receiver if there is a dramatic temperature increase. That heat also powers the sensor itself, without replacing batteries. The team printed the substances onto ordinary paper to create a sensor for just $ 0.40.But improving coordination among the different agencies involved in firefighting is even more crucial to address, says Graham Kent, an earthquake expert at theUniversityofNevada,Reno, who was not part of the study.Kentis director of ALERTWildfire, a network that uses cameras and crowd sourcing to watch for fires inCalifornia,NevadaandOregon. “The whole way that you respond to a fire until it's put out is like a ballet," he says. “You'd have to choreograph (设计) it just so, with resources precisely used at the right time and place and in the right order from detection to confirmation to assignment to extinguishment (熄灭).Fire detection is just step one.Wang says his team's next steps are to extend the device'ssignal range beyond the current 100 meters, which can limit practical use, and to develop a protective shield for it. The transmitter's effectiveness, he notes, will also need to be examined in the field ahead.8. What does the underlined word “gravity” in paragraph 1 probably mean?A. Pull.B. Extinction.C. Popularity.D. Severity.9. What do we know about the sensor?A. Its price remains high.B. Its batteries are replaceable.C. It can detect fires earlier and easier.D. It can reduce firefighters' pain.10. What doesKentmean in paragraph 4?A. Firefighting is easy but crucial.B. Fire detection resources are rich.C. Putting out a fire is an orderly activity.D. Technology is the key to extinguishing a fire.11. What's the plan for the new sensor according to Wang?A. Improving and testing it.B. Limiting its use and transmission.C. Examing and reducing its signal range.D. Getting it on the market ahead of time.DExperts are warning about the risks of extremely picky(挑剔的)eating after a teenager living on a diet of chips and crisps developed lasting sight loss. Eye doctors inBristolcared for the 17-year-old after his sight had gone to the point of blindness. Tests showed he had serious vitamin deficiency(缺乏). Dr. Denize Atan, who treated him at the hospital, said, “His diet was basically a portion of chips from the local fish and chip shop every day. He also used to snack on crisps and sometimes white bread and ham, and not really any fruit and vegetables.”The teenager saw his doctor at the age of 14 because he had been feeling tired and unwell. At that time he suffered from vitamin B12 deficiency, but he did not stick with the treatment or improve his poor diet. Three years later, he was taken to theBristolEyeHospitalbecause of progressive sight loss.He was not overweight or underweight, but he had lost minerals from his bones, which was really quite shocking for a boy of his age. In terms of his sight loss, he met the standards of being blind. “He had blind spots right in the middle of his sight,” said Dr Denize Atan, “That means he can’t drive and would find it reallyarduousto read, watch TV or recognize faces.”Dr Denize Atan said that parents should learn about the harm that can be caused by picky eating, and turn to experts for help. For those who are concerned , she advised, “It’s best not to be anxious about picky eating , and instead calmly introduce one or two new foods with every meal.” She said multivitamin tablets can supplement(补充) a diet, but cannot take the place of eating healthily. “It’s much better to take in vitamins through a varied and balanced diet,” she said, adding that too manycertain vitamins , including vitamin A, can be harmful ,“so you don’t want to overdo it.”12. What does Dr Denize Atan imply in paragraph 1?A. The diet of the boy is not balanced.B. Fruit and vegetables are rich in vitamins.C. Picky eating is common among teenagers.D. The cause of the boy’s disease is unknown.13. Why did the boy go to see his doctor at the age of 14?A. To improve his poor diet.B. To get some help to lose weight.C. To be treated for his discomfort.D. To slow down his progressive sight loss.14. What does the underlined word “arduous” in paragraph 3 probably mean?A. Important.B. Easy.C. Necessary.D. Difficult.15. What does the last paragraph mainly talk about?A. Reasons why the boy is seriously ill.B.Suggestions for the boy’s family to care for him.C. Advice for parents worried about picky eating.D. Waysof taking in enough vitamins and minerals.第二节（共5小题；每小题2分，满分10分）阅读下面短文，从短文后的选项中选出可以填入空白处的最佳选项。

2020-2021学年九年级化学4月月考1

2020-2021学年九年级化学4月月考1

湛江市二中港城中学2020—2021学年度第二学期九年级化学学科4月月考试题考试时间：60分钟考试范围：1-12单元命题人：lml 审题人：lyb可能用到的相对原子质量：H—1 C—12 O—16 S—32 N—14 K—39 Ca—40 Cu—64 Zn-65一、选择题（共15题，每小题只有一个正确选项，每小题3分，共45分）1.下列物质的用途与其化学性质无关的是（）A. 酒精用于杀菌B.汽油用于汽车燃料C.干冰用于人工降雨D.氮气用于填充电灯泡2. .下列操作错误的是（）A.B. C. D.3.分类是学习和研究化学的常用方法。

下列物质分类正确的是（）选项A B C D物质淀粉、CO2铁水、水银H2O2、酒精（C2H5OH）冰水混合物、稀有气体类别有机物单质氧化物混合物4.如图中的X、Y、Z分别表示的是水、石灰水、稀盐酸三种物质的近似pH．下列判断错误的是（）A．X应该是稀盐酸B．Y应该是水C．Z应该是石灰水D．40%的氢氧化钠溶液的pH可能会介于Y和Z之间5.小深同学用思维导图梳理了Na2CO3的相关知识，其中描述错误的是（）6.垃圾分类，文明从点滴做起。

下列废弃物需投入此标识“”垃圾箱的是（）A.过期药品B.废旧电池C. 矿泉水瓶D. 剩菜剩饭7.同学们夏季郊游时，发现稻田里的水稻空瘪并倒下了一片，都认为应该向稻田中施用的复合肥是（）A．NH4NO3B．KNO3C．K3PO4D．KCl8. 下列化学符号所表示的含义正确的是（）A．Cl可表示氯气B．N2表示2个氮原子点燃酒精灯称量9.5g氯化钠时，指针右偏滴管使用后放回原瓶收集较为纯净的氧气通电溶解度/g温度/℃溶质 质量分数 冷却时间NaOH 溶液质量/g溶液的质量/gC ．2Al 3+表示2个铝离子D ．SO 2只能表示二氧化硫由硫、氧两种元素组成 9.下列实验现象、化学方程式、反应类型都正确的是( )A ．电解水时，正、负极产生气体体积比是1:2： 2H 2O == H 2↑+O 2（分解反应）B ．细铁丝在氧气中燃烧，火星四射，生成四氧化三铁：3Fe + 2O 2 == Fe 3O 4 （化合反应）C ．铁和稀盐酸反应，有气泡冒出，溶液由无色变为浅绿色：Fe ＋2HCl == FeCl 2＋H 2↑（置换反应）D ．往澄清石灰水中通入CO 2，澄清石灰水变浑浊：Ca(OH)2+CO 2 ==CaCO 3↓+H 2O （复分解反应） 10. 温室效应和酸雨是两大环境问题，造成温室效应和酸雨的物质分别是（ ） A ．CO 2 、 CO B ．CH 4 、 CO 2 C. CO 2 、 NO 2 D ．CO 、SO 211. 下列关于碳和碳的氧化物说法正确的是（ ） A. 金刚石、石墨、C 60都是由碳原子构成的 B. CO 和CO 2组成元素相同，化学性质也相同C. CO 还原CuO 时，先加热，再通CO ，避免CO 逸出污染空气D. 档案的书写通常使用碳素墨水是因为常温下碳的化学性质不活泼12. 乙硫醇（C 2H 6S ）具有刺激性的蒜臭味，通常被加入煤气等做臭味指示剂，下列说法错误的是（ ） A ．乙硫醇中氢元素质量分数最大B ．乙硫醇分子中碳、氢、硫原子的个数比2：6：1C ．乙硫醇是由碳、氢、硫元素组成的D ．乙硫醇的相对分子质量＝12×2+1×6+32×1 13. 化学与生活、生产息息相关，下列说法正确的是（ ）A. 富含蛋白质的食物如花生等长时间存放容易产生黄曲霉毒素 。

湛江二中2019-2020学年度初三上第一次月考数学试卷及答案

湛江二中2019-2020学年度初三上第一次月考数学试卷及答案

湛江二中2019-2020学年度初三上第一次月考数学试卷及答案度上学期第一次月考初三数学试卷（考试时间100分钟，满分120分）一、选择题（共10小题，每小题3分，共30分）1.下列各图中，既是中心对称图形又是轴对称图形的是（ ）2.点P （2，3）关于原点的对称点P 1的坐标是（ ）A ．（-3，-2）B ．（2，-3）C ．（-2，-3）D ．（-2，3） 3. 如图，△ABC 内接于⊙O ，若∠A=40°，则∠BOC 的度数为（ ） A ．20° B ．40° C ．50° D ．80°4.⊙O 的直径为15cm ，O 点与P 点的距离为8cm ，点P 的位置（ ） A.在⊙O 外 B.在⊙O 上 C.在⊙O 内 D.不能确定5.把抛物线y ＝2x 2先向左平移3个单位，再向上平移4个单位，所得抛物线的函数表达式为（ ）A ．y ＝2(x+3)2+4 B ．y ＝2(x+3)2－4 C ．y ＝2(x －3)2－4 D ．y ＝2(x －3)2+4 6.用配方法解方程2210x x +-=，下列配方正确的是( )A .2(1)1x +=B . 2(1)2x +=C .2(1)2x -=D .2(1)1x -=7.某为发展教育事业，加强了对教育经费的投入，年投入3 000万元，预计年投入5 000万元．设教育经费的年平均增长率为x ，根据题意，下面所列方程正确的是（ ） A ．23000(1)5000x +=B ．230005000x =C ．23000(1)5000x +=％ D.23000(1)3000(1)5000x x +++=8.已知⊙O 的半径为5，且圆心O 到直线l 的距离是方程x 2-4x-12=0的一个根，则直线l 与圆的位置关系是（ ）等边三角形A 平行四边形B 矩形C等腰梯形D第3题图A.相交B.相切C.相离D.无法确定9.如图，某小区在宽20m ，长32m 的矩形地面上修筑同样宽的人行道（图中阴影部分），余下的部分种上草坪．要使草坪的面积为540m 2，则道路的宽为（ ）A.50mB.5mC.2mD.1m10.二次函数c bx ax y ++=2的图象如图所示，则abc ，ac b 42-，b a +2，c b a ++这四个式子中，值为正数的有（ ）A ．1个B ．2个C ．3个二、填空题（共6小题，每小题4分，共24分）11.方程21x =的解是 。

广东省湛江市霞山区湛江二中港城中学2019-2020学年九年级下学期开学考试化学试题(word无答案)

广东省湛江市霞山区湛江二中港城中学2019-2020学年九年级下学期开学考试化学试题(word无答案)

广东省湛江市霞山区湛江二中港城中学2019-2020学年九年级下学期开学考试化学试题一、单选题(★★) 1 . 下列生产活动中主要发生化学变化的是（）A．海水晒盐B．水力发电C．粮食酿酒D．液态空气制氧气(★) 2 . 下列实验操作不正确的是A．加热液体B．稀释浓硫酸C．蒸发食盐水D．检查装置气密性(★) 3 . 下列化学用语书写正确的是（）A．两个氮原子：2N2B．两个氢分子：2HC．氧化铝的化学式：Al2O3D．一个钙离子：Ca-2(★) 4 . 硅是重要的半导体材料。

X+H 23HCl+Si（高纯）是工业制硅流程中的一个化学反应方程式，则X为（）A．SiCl B．SiCl3C．SiHCl3D．SiH2Cl3(★) 5 . 蔗糖（C 12H 22O 11）是一种常用的食品甜味剂。

下列关于蔗糖的说法正确的是（）A．蔗糖是由碳、氢、氧三种元素组成B．蔗糖中含有45个原子C．蔗糖中氢元素的质量分数最高D．蔗糖的相对分子质量为342g(★★) 6 . 如图是CO与CuO反应的实验装置，下列关于该实验说法正确的是（）①玻璃管中黑色固体变成了红色②CO被还原为CO 2③玻璃管中发生的反应为置换反应④既有效地防止了CO对空气的污染，又充分利用了能源A．①②B．①④C．②④D．③④(★★) 7 . 下列物质的名称、俗称、化学式、物质分类完全对应正确的是（）名称俗名化学式物质分类A氧化钙生石灰CaO碱B碳酸钙石灰石CaCO3盐C乙醇酒精C2H5OH氧化物D固态二氧化碳干冰CO2氧化物A．A B．B C．C D．D(★★) 8 . 2019年3月30日，四川凉山木里县突发森林火灾，下列说法错误的是A．森林地表腐质层的可燃性气体在雷击作用下达到着火点而燃烧，引发森林火灾B．森林大火不易扑灭是因为山势陡峭，树林茂密，难以通过砍伐树木形成隔离带C．出动直升机开展吊桶投水扑灭山火，主要目的是降低可燃物的着火点D．消防人员灭火时要防止被森林大火灼烧，并戴好防护面罩避免吸入有害物质(★★) 9 . 下表是某同学测定的几种试剂在常温时的pH，下列说法错误的是（）试剂蒸馏水食盐水盐酸草木灰溶液氯化铵溶液pH771105A．草木灰溶液显碱性B．氯化铵溶液显酸性C．盐酸与草木灰溶液不发生化学反应D．盐溶液可能呈中性，也可能呈酸性或碱性(★★★★) 10 . 向 AgNO 3、Cu（NO 3）2、Mg（NO 3）2的混合溶液中，加入一定量的铁粉，充分反应后过滤，滤液呈蓝色。

广东省湛江市第二中学九年级数学下学期4月月考试题(无答案) 北师大版

广东省湛江市第二中学九年级数学下学期4月月考试题(无答案) 北师大版

广东省湛江市第二中学2013届九年级数学下学期4月月考试题（无答案） 北师大版（答题时间90分钟，）一、选择题。

（每小题4分，共12题，）1、－5的相反数是（ ）A ．5B ．51C ．－5D ．51-2、下面的计算正确的是（ ）A ．633a a a =+B ．523)(a a = C ．2222a a a =+ D ．a 5a 6=÷a 3、光的速度约为30万公里每秒，30万用科学记数法表示为（ ）A 、 5103⨯B 、6103⨯C 、 7103⨯D 、8103⨯4、一个几何体的三视图如图所示，那么这个几何体是（ ）。

5、将一副三角板按图中的方式叠放，则角α等于（ ）A ．75B ．60C ．45D ．306、如图，在半径为5cm 的⊙O 中，圆心O 到弦AB 的距离为3cm ，则弦AB 的长是（ ）A ．4cmB ．6cmC ．8cmD ．10cm7、下列命题中，真命题是（ ）A 、两条对角线相等的四边形是矩形；B 、两条对角线互相垂直的四边形是菱形；C 、两条对角线互相垂直且相等的四边形是正方形；D 、两条对角线互相平分的四边形是平行四边形；8、不等式2121≥+x 的解集在数轴上表示正确的是（ ）9、小明用一枚均匀的硬币进行试验，连续抛三次，结果都是．．正面朝上．．．．的概率是（ ） A 、21 B 、41 C 、61 D 、81 10、下列图形即使轴对称图形又是中心对称图形的有（ ）①平行四边形；②正方形；③等腰梯形；④菱形；⑤正六边形A 、1个B 、2个C 、3个D 、4个 11、二次函数322--=x x y 与y 轴的交点坐标为（ ）A 、无交点B 、（0，-1）C 、（-3，0）D 、（0，-3）12、对正整数n ，记!123......n n =⨯⨯⨯⨯，则1!2!3!......10!+++的末尾数为（ ）A 、0B 、1C 、3D 、5二、填空题。

（共4题，每题4分）13、数据3、3、4、5、5的方差是_____________。

广东省湛江市2019-2020学年中考数学三月模拟试卷含解析

广东省湛江市2019-2020学年中考数学三月模拟试卷含解析

广东省湛江市2019-2020学年中考数学三月模拟试卷一、选择题（本大题共12个小题，每小题4分，共48分．在每小题给出的四个选项中，只有一项是符合题目要求的．）1．如图，矩形ABCD中，AB=10，BC=5，点E，F，G，H分别在矩形ABCD各边上，且AE=CG，BF=DH，则四边形EFGH周长的最小值为（）A．55B．105C．103D．1532．矩形ABCD的顶点坐标分别为A(1，4)、B(1，1)、C(5，1)，则点D的坐标为( )A．(5，5) B．(5，4) C．(6，4) D．(6，5)3．如图，直线a∥b，一块含60°角的直角三角板ABC（∠A＝60°）按如图所示放置．若∠1＝55°，则∠2的度数为（）A．105°B．110°C．115°D．120°4．若x＞y，则下列式子错误的是（）A．x﹣3＞y﹣3 B．﹣3x＞﹣3y C．x+3＞y+3 D．x y > 335．下列计算错误的是()A．a•a=a2B．2a+a=3a C．(a3)2=a5D．a3÷a﹣1=a46．在△ABC中，点D、E分别在AB、AC上，如果AD＝2，BD＝3，那么由下列条件能够判定DE∥BC 的是( )A．DEBC＝23B．DEBC＝25C．AEAC＝23D．AEAC＝257．如图，在△ABC中，∠CAB＝75°，在同一平面内，将△ABC绕点A逆时针旋转到△AB′C′的位置，使得CC′∥AB，则∠CAC′为（）A．30°B．35°C．40°D．50°8．如图，△ABC中，AD⊥BC，AB=AC，∠BAD=30°，且AD=AE，则∠EDC等于（）A．10°B．12.5°C．15°D．20°9．如图，△ABC中AB两个顶点在x轴的上方，点C的坐标是（﹣1，0），以点C为位似中心，在x轴的下方作△ABC的位似图形△A′B′C′，且△A′B′C′与△ABC的位似比为2：1．设点B的对应点B′的横坐标是a，则点B的横坐标是（）A．12a-B．1(1)2a-+C．1(1)2a--D．1(3)2a-+10．如图是某公园的一角，∠AOB=90°，弧AB的半径OA长是6米，C是OA的中点，点D在弧AB上，CD∥OB，则图中休闲区（阴影部分）的面积是（）A．91032π⎛⎝米2B．932π⎛⎝米2C．9632π⎛⎝米2D．(693π-米211．若顺次连接四边形ABCD各边中点所得的四边形是菱形，则四边形ABCD一定是（）A．矩形B．菱形C．对角线互相垂直的四边形D．对角线相等的四边形12．若实数m满足22210⎛⎫++=⎪⎝⎭mm，则下列对m值的估计正确的是（）A．﹣2＜m＜﹣1 B．﹣1＜m＜0 C．0＜m＜1 D．1＜m＜2 二、填空题：（本大题共6个小题，每小题4分，共24分．）13．如图，点A，B是反比例函数y=kx（x＞0）图象上的两点，过点A，B分别作AC⊥x轴于点C，BD⊥x轴于点D，连接OA，BC，已知点C（2，0），BD=2，S△BCD=3，则S△AOC=__．14．点G 是三角形ABC 的重心，AB a =u u u r r ，AC b =u u u r r ，那么BG u u u r=_____．15．如图，在扇形AOB 中∠AOB=90°，正方形CDEF 的顶点C 是弧AB 的中点，点D 在OB 上，点E 在OB 的延长线上，当扇形AOB 的半径为22时，阴影部分的面积为__________．16．如图，已知正方形ABCD 的边长为4，⊙B 的半径为2，点P 是⊙B 上的一个动点，则PD ﹣12PC 的最大值为_____．17．计算：364-的值是______________． 18．当x=_________时，分式323xx -+的值为零． 三、解答题：（本大题共9个小题，共78分，解答应写出文字说明、证明过程或演算步骤． 19．（6分）如图，己知AB 是的直径，C 为圆上一点，D 是的中点，于H ，垂足为H ，连交弦于E ，交于F ，联结.(1)求证：.(2)若，求的长.20．（6分）如今，旅游度假成为了中国人庆祝传统春节的一项的“新年俗”，山西省旅发委发布的《2018年“春节”假日旅游市场总结分析报告》中称：山西春节旅游供需两旺，实现了“旅游接待”与“经济效益”的双丰收，请根据图表信息解决问题：（1）如图1所示，山西近五年春节假日接待海内外游客的数量逐年增加，2018年首次突破了“千万”大关，达到万人次，比2017年春节假日增加万人次．（2）2018年2月15日﹣20日期间，山西省35个重点景区每日接待游客数量如下：日期2月15日（除夕）2月16日（初一）2月17日（初二）2月18日（初三）2月19日（初四）2月20日（初五）日接待游客数量（万人次）7.56 82.83 119.51 84.38 103.2 151.55这组数据的中位数是万人次．（3）根据图2中的信息预估：2019年春节假日山西旅游总收入比2018年同期增长的百分率约为，理由是．（4）春节期间，小明在“青龙古镇第一届新春庙会”上购买了A，B，C，D四枚书签（除图案外完全相同）．正面分别印有“剪纸艺术”、“国粹京剧”、“陶瓷艺术”、“皮影戏”的图案（如图3），他将书签背面朝上放在桌面上，从中随机挑选两枚送给好朋友，求送给好朋友的两枚书签中恰好有“剪纸艺术”的概率．21．（6分）我市某学校在“行读石鼓阁”研学活动中，参观了我市中华石鼓园，石鼓阁是宝鸡城市新地标．建筑面积7200平方米，为我国西北第一高阁．秦汉高台门阙的建筑风格，追求稳定之中的飞扬灵动，深厚之中的巧妙组合，使景观功能和标志功能融为一体．小亮想知道石鼓阁的高是多少，他和同学李梅对石鼓阁进行测量．测量方案如下：如图，李梅在小亮和“石鼓阁”之间的直线BM 上平放一平面镜，在镜面上做了一个标记，这个标记在直线BM 上的对应位置为点C ，镜子不动，李梅看着镜面上的标记，她来回走动，走到点D 时，看到“石鼓阁”顶端点A 在镜面中的像与镜面上的标记重合，这时，测得李梅眼睛与地面的高度ED=1.6米，CD=2.2米，然后，在阳光下，小亮从D 点沿DM 方向走了29.4米，此时“石鼓阁”影子与小亮的影子顶端恰好重合，测得小亮身高1.7米，影长FH=3.4米．已知AB ⊥BM ，ED ⊥BM ，GF ⊥BM ，其中，测量时所使用的平面镜的厚度忽略不计，请你根据题中提供的相关信息，求出“石鼓阁”的高AB 的长度．22．（8分）如图，一个长方形运动场被分隔成A 、B 、A 、B 、C 共5个区，A 区是边长为am 的正方形，C 区是边长为bm 的正方形．列式表示每个B 区长方形场地的周长，并将式子化简；列式表示整个长方形运动场的周长，并将式子化简；如果a ＝20，b ＝10，求整个长方形运动场的面积．23．（8分）太阳能光伏建筑是现代绿色环保建筑之一，老张准备把自家屋顶改建成光伏瓦面，改建前屋顶截面△ABC 如图2所示，BC=10米，∠ABC=∠ACB=36°，改建后顶点D 在BA 的延长线上，且∠BDC=90°，求改建后南屋面边沿增加部分AD 的长．（结果精确到0.1米）24．（10分）先化简2211a a a a ⎛⎫-÷⎪--⎝⎭，然后从22a -≤<中选出一个合适的整数作为a 的值代入求值． 25．（10分）今年5月，某大型商业集团随机抽取所属的m 家商业连锁店进行评估，将各连锁店按照评估成绩分成了A 、B 、C 、D 四个等级，绘制了如图尚不完整的统计图表．评估成绩n（分）评定等级频数90≤n≤100 A 280≤n＜90 B70≤n＜80 C 15n＜70 D 6根据以上信息解答下列问题：（1）求m的值；（2）在扇形统计图中，求B等级所在扇形的圆心角的大小；（结果用度、分、秒表示）（3）从评估成绩不少于80分的连锁店中任选2家介绍营销经验，求其中至少有一家是A等级的概率．26．（12分）如图，在⊙O中，AB为直径，OC⊥AB，弦CD与OB交于点F，在AB的延长线上有点E，且EF=ED．（1）求证：DE是⊙O的切线；（2）若tanA=12，探究线段AB和BE之间的数量关系，并证明；（3）在（2）的条件下，若OF=1，求圆O的半径．27．（12分）二次函数y=ax2+bx+c（a，b，c为常数，且a≠1）中的x与y的部分对应值如表x﹣1 1 1 3y ﹣1 3 5 3下列结论：①ac＜1；②当x＞1时，y的值随x值的增大而减小．③3是方程ax2+（b﹣1）x+c=1的一个根；④当﹣1＜x＜3时，ax2+（b﹣1）x+c＞1．其中正确的结论是．参考答案一、选择题（本大题共12个小题，每小题4分，共48分．在每小题给出的四个选项中，只有一项是符合题目要求的．）1．B【解析】作点E关于BC的对称点E′，连接E′G交BC于点F，此时四边形EFGH周长取最小值，过点G作GG′⊥AB 于点G′，如图所示，∵AE=CG，BE=BE′，∴E′G′=AB=10，∵GG′=AD=5，∴2255E G GG''+'=∴C四边形EFGH5【点睛】本题考查了轴对称-最短路径问题，矩形的性质等，根据题意正确添加辅助线是解题的关键．2．B【解析】【分析】由矩形的性质可得AB∥CD，AB=CD，AD=BC，AD∥BC，即可求点D坐标．【详解】解：∵四边形ABCD是矩形∴AB∥CD，AB=CD，AD=BC，AD∥BC，∵A（1，4）、B（1，1）、C（5，1），∴AB∥CD∥y轴，AD∥BC∥x轴∴点D坐标为（5，4）故选B．【点睛】本题考查了矩形的性质，坐标与图形性质，关键是熟练掌握这些性质.3．C【解析】【分析】如图，首先证明∠AMO=∠2，然后运用对顶角的性质求出∠ANM=55°；借助三角形外角的性质求出∠AMO即可解决问题．【详解】如图，对图形进行点标注.∵直线a∥b，∴∠AMO=∠2；∵∠ANM=∠1，而∠1=55°，∴∠ANM=55°，∴∠2=∠AMO=∠A+∠ANM=60°+55°=115°，故选C.本题考查了平行线的性质，三角形外角的性质，熟练掌握和灵活运用相关知识是解题的关键.4．B【解析】根据不等式的性质在不等式两边加（或减）同一个数（或式子），不等号的方向不变；不等式两边乘（或除以）同一个正数，不等号的方向不变；不等式两边乘（或除以）同一个负数，不等号的方向改变即可得出答案：A、不等式两边都减3，不等号的方向不变，正确；B、乘以一个负数，不等号的方向改变，错误；C、不等式两边都加3，不等号的方向不变，正确；D、不等式两边都除以一个正数，不等号的方向不变，正确．故选B．5．C【解析】【分析】【详解】解：A、a•a=a2，正确，不合题意；B、2a+a=3a，正确，不合题意；C、（a3）2=a6，故此选项错误，符合题意；D、a3÷a﹣1=a4，正确，不合题意；故选C．【点睛】本题考查幂的乘方与积的乘方；合并同类项；同底数幂的乘法；负整数指数幂．6．D【解析】【分析】根据平行线分线段成比例定理的逆定理,当AD AEDB EC=或AD AEAB AC=时,DE BDP,然后可对各选项进行判断.【详解】解：当AD AEDB EC=或AD AEAB AC=时,DE BDP,即23AEEC=或25AEAC=.所以D选项是正确的.本题考查了平行线分线段成比例定理:三条平行线截两条直线,所得的对应线段成比例.也考查了平行线分线段成比例定理的逆定理.7．A【解析】【分析】根据旋转的性质可得AC=AC,∠BAC=∠BAC',再根据两直线平行,内错角相等求出∠ACC=∠CAB,然后利用等腰三角形两底角相等求出∠CAC,再求出∠BAB=∠CAC,从而得解【详解】∵CC′∥AB，∠CAB＝75°，∴∠C′CA＝∠CAB＝75°，又∵C、C′为对应点，点A为旋转中心，∴AC＝AC′，即△ACC′为等腰三角形，∴∠CAC′＝180°﹣2∠C′CA＝30°．故选A．【点睛】此题考查等腰三角形的性质，旋转的性质和平行线的性质，运用好旋转的性质是解题关键8．C【解析】试题分析：根据三角形的三线合一可求得∠DAC及∠ADE的度数，根据∠EDC=90°-∠ADE即可得到答案．∵△ABC中，AD⊥BC，AB=AC，∠BAD=30°，∴∠DAC=∠BAD=30°，∵AD=AE（已知），∴∠ADE=75°∴∠EDC=90°-∠ADE=15°．故选C．考点：本题主要考查了等腰三角形的性质，三角形内角和定理点评：解答本题的关键是掌握等腰三角形的顶角平分线、底边上的中线、底边上的高相互重合．9．D【解析】【分析】设点B的横坐标为x，然后表示出BC、B′C的横坐标的距离，再根据位似变换的概念列式计算．【详解】设点B的横坐标为x，则B、C间的横坐标的长度为﹣1﹣x，B′、C间的横坐标的长度为a+1，∵△ABC放大到原来的2倍得到△A′B′C，∴2（﹣1﹣x）＝a+1，解得x＝﹣12（a+3），故选：D．【点睛】本题考查了位似变换，坐标与图形的性质，根据位似变换的定义，利用两点间的横坐标的距离等于对应边的比列出方程是解题的关键．10．C【解析】【详解】连接OD，∵弧AB的半径OA长是6米，C是OA的中点，∴OC=12OA=12×6=1．∵∠AOB=90°，CD∥OB，∴CD⊥OA．在Rt△OCD中，∵OD=6，OC=1，∴2222CD OD OC6333=-=-=．又∵CD333sin DOCOD∠===，∴∠DOC=60°．∴2606193336336022DOCAODS S Sππ∆⋅⋅=-=-⨯⨯=-阴影扇形（米2）．故选C．11．C 【解析】【分析】如图，根据三角形的中位线定理得到EH∥FG，EH=FG，EF=12BD，则可得四边形EFGH是平行四边形，若平行四边形EFGH是菱形，则可有EF=EH，由此即可得到答案．【点睛】如图，∵E，F，G，H分别是边AD，DC，CB，AB的中点，∴EH=12AC，EH∥AC，FG=12AC，FG∥AC，EF=12BD，∴EH∥FG，EH=FG，∴四边形EFGH是平行四边形，假设AC=BD，∵EH=12AC，EF=12BD，则EF=EH，∴平行四边形EFGH是菱形，即只有具备AC=BD即可推出四边形是菱形，故选D．【点睛】本题考查了中点四边形，涉及到菱形的判定，三角形的中位线定理，平行四边形的判定等知识，熟练掌握和灵活运用相关性质进行推理是解此题的关键．12．A【解析】试题解析：∵222(1)0mm++=，∴m2+2+4m=0，∴m2+2=-4m，∴方程的解可以看作是函数y=m2+2与函数y=-4m，作函数图象如图，在第二象限，函数y=m2+2的y值随m的增大而减小，函数y=-4m的y值随m的增大而增大，当m=-2时y=m2+2=4+2=6，y=-4m=-42-=2，∵6＞2，∴交点横坐标大于-2，当m=-1时，y=m2+2=1+2=3，y=-4m=-41-=4，∵3＜4，∴交点横坐标小于-1，∴-2＜m＜-1．故选A．考点：1.二次函数的图象；2.反比例函数的图象．二、填空题：（本大题共6个小题，每小题4分，共24分．）13．1．【解析】【分析】由三角形BCD为直角三角形，根据已知面积与BD的长求出CD的长，由OC+CD求出OD的长，确定出B的坐标，代入反比例解析式求出k的值，利用反比例函数k的几何意义求出三角形AOC面积即可．【详解】∵BD⊥CD，BD=2，∴S△BCD=12BD•C D=2，即CD=2．∵C（2，0），即OC=2，∴OD=OC+CD=2+2=1，∴B（1，2），代入反比例解析式得：k=10，即y=10x，则S△AOC=1．故答案为1．【点睛】本题考查了反比例函数系数k的几何意义，以及反比例函数图象上点的坐标特征，熟练掌握反比例函数k 的几何意义是解答本题的关键．14．1233b ar r．【解析】【分析】根据题意画出图形，由AB a =u u u v v ，AC b =u u u v v ，根据三角形法则，即可求得BD u u u v 的长，又由点G 是△ABC 的重心，根据重心的性质，即可求得．【详解】如图：BD 是△ABC 的中线，∵AC b =u u u v v， ∴AD u u u v =12b v ， ∵AB a =u u u v v ，∴BD u u u v =12b v ﹣a v ， ∵点G 是△ABC 的重心，∴BG u u u v =23BD u u u v =13b v ﹣23a v ， 故答案为：13b v ﹣23a v ．【点睛】本题考查了三角形的重心的性质：三角形的重心到三角形顶点的距离是它到对边中点的距离的2倍，本题也考查了向量的加法及其几何意义，是基础题目．15．π﹣1【解析】【分析】根据勾股定理可求OC 的长，根据题意可得出阴影部分的面积=扇形BOC 的面积-三角形ODC 的面积，依此列式计算即可求解．【详解】连接OC∵在扇形AOB 中∠AOB ＝90°，正方形CDEF 的顶点C 是弧AB 的中点，∴∠COD ＝45°，∴OC 2＝2 ，∴CD ＝OD ＝1，∴阴影部分的面积＝扇形BOC 的面积﹣三角形ODC 的面积＝24522360gπ（）﹣12×11＝π﹣1．故答案为π﹣1．【点睛】本题考查正方形的性质和扇形面积的计算，解题关键是得到扇形半径的长度．16．1【解析】分析: 由PD−12PC＝PD−PG≤DG，当点P在DG的延长线上时，PD−12PC的值最大，最大值为DG＝1．详解: 在BC上取一点G，使得BG＝1，如图，∵221PBBG==，422BCPB==，∴PB BC BG PB=，∵∠PBG＝∠PBC，∴△PBG∽△CBP，∴12 PG BGPC PB==，∴PG＝12 PC，当点P在DG的延长线上时，PD−12PC的值最大，最大值为DG2243+1．故答案为1点睛: 本题考查圆综合题、正方形的性质、相似三角形的判定和性质等知识，解题的关键是学会构建相似三角形解决问题，学会用转化的思想思考问题，把问题转化为两点之间线段最短解决，题目比较难，属于中考压轴题．17．-1【解析】=－1．故答案为：－1．解：36418．2【解析】【分析】根据若分式的值为零，需同时具备两个条件：（1）分子为1；（2）分母不为1计算即可．【详解】解：依题意得：2﹣x=1且2x+2≠1．解得x=2，故答案为2．【点睛】本题考查的是分式为1的条件和一元二次方程的解法，掌握若分式的值为零，需同时具备两个条件：（1）分子为1；（2）分母不为1是解题的关键．三、解答题：（本大题共9个小题，共78分，解答应写出文字说明、证明过程或演算步骤．19．（1）证明见解析；（2）【解析】【分析】（1）由题意推出再结合，可得△BHE～△BCO.（2）结合△BHE～△BCO ，推出带入数值即可.【详解】（1）证明：∵为圆的半径，是的中点，∴,,∵,∴，∴,∴,∵,∴,∴,又∵,∴∽．（2）∵∽，∴,∵，,∴得，解得，∴.【点睛】本题考查的知识点是圆与相似三角形，解题的关键是熟练的掌握圆与相似三角形.20．（1）1365.45、414.4（2）93.79（3）30%；近3年平均涨幅在30%左右，估计2019年比2018年同比增长约30%（4）1 2【解析】【分析】（1）由图1可得答案；（2）根据中位数的定义求解可得；（3）由近3年平均涨幅在30%左右即可做出估计；（4）根据题意先画出树状图，得出共有12种等可能的结果数，再利用概率公式求解可得．【详解】（1）2018年首次突破了“千万”大关，达到1365.45万人次，比2017年春节假日增加1365.45﹣951.05=414.4万人次．故答案为：1365.45、414.4；（2）这组数据的中位数是84.38+103.22=93.79万人次，故答案为：93.79；（3）2019年春节假日山西旅游总收入比2018年同期增长的百分率约为30%，理由是：近3年平均涨幅在30%左右，估计2019年比2018年同比增长约30%，故答案为：30%；近3年平均涨幅在30%左右，估计2019年比2018年同比增长约30%．（4）画树状图如下：则共有12种等可能的结果数，其中送给好朋友的两枚书签中恰好有“剪纸艺术”的结果数为6，所以送给好朋友的两枚书签中恰好有“剪纸艺术”的概率为12．【点睛】本题考查了列表法与树状图法：利用列表法和树状图法展示所有可能的结果求出n，再从中选出符合事件A或B的结果数目m，求出概率，也考查了条形统计图与样本估计总体．21．“石鼓阁”的高AB的长度为56m．【解析】【分析】根据题意得∠ABC=∠EDC=90°，∠ABM=∠GFH=90°，再根据反射定律可知：∠ACB=∠ECD，则△ABC∽△EDC，根据相似三角形的性质可得ABBC=EDDC，再根据∠AHB=∠GHF，可证△ABH∽△GFH，同理得ABBH=GFFH，代入数值计算即可得出结论.【详解】由题意可得：∠ABC=∠EDC=90°，∠ABM=∠GFH=90°，由反射定律可知：∠ACB=∠ECD，则△ABC∽△EDC，∴ABBC=EDDC，即ABBC=1.62.2①，∵∠AHB=∠GHF，∴△ABH∽△GFH，∴ABBH=GFFH，即2.229.43.4ABBC+++=1.73.4②，联立①②，解得：AB=56，答：“石鼓阁”的高AB的长度为56m．【点睛】本题考查了相似三角形的判定与性质，解题的关键是熟练的掌握相似三角形的判定与性质. 22．（1）4a（2）8a（3）1500S=【解析】试题分析：（1）结合图形可得矩形B的长可表示为：a+b，宽可表示为：a-b，继而可表示出周长；（2）根据题意表示出整个矩形的长和宽，再求周长即可；（3）先表示出整个矩形的面积，然后代入计算即可．试题解析：（1）矩形B 的长可表示为：a+b ，宽可表示为：a-b ，∴每个B 区矩形场地的周长为：2（a+b+a-b ）=4a ；（2）整个矩形的长为a+a+b=2a+b ，宽为：a+a-b=2a-b ，∴整个矩形的周长为：2（2a+b+2a-b ）=8a ；（3）矩形的面积为：S=（2a+b ）（2a-b ）=224a b - ，把20a =，10b =代入得，S=4×202-102=4×400-100=1500. 点睛：本题考查了列代数式的知识，属于基础题，解答本题的关键是结合图形表示出各矩形的长和宽． 23．1.9米【解析】试题分析：在直角三角形BCD 中，由BC 与sinB 的值，利用锐角三角函数定义求出CD 的长，在直角三角形ACD 中，由∠ACD 度数，以及CD 的长，利用锐角三角函数定义求出AD 的长即可．试题解析：∵∠BDC=90°，BC=10，sinB=， ∴CD=BC•sinB=10×0.2=5.9，∵在Rt △BCD 中，∠BCD=90°﹣∠B=90°﹣36°=54°， ∴∠ACD=∠BCD ﹣∠ACB=54°﹣36°=18°， ∴在Rt △ACD 中，tan ∠ACD=， ∴AD=CD•tan ∠ACD=5.9×0.32=1.888≈1.9（米），则改建后南屋面边沿增加部分AD 的长约为1.9米．考点：解直角三角形的应用24．-1【解析】【分析】先化简，再选出一个合适的整数代入即可，要注意a 的取值范围.【详解】 解：2211a a a a ⎛⎫-÷ ⎪--⎝⎭ (1)(1)12a a a a a ---=•- 1(1)12a a a a a -+-=•- 2a =， 当2a =-时，原式212-==-． 【点睛】 本题考查的是代数式的求值，熟练掌握代数式的化简是解题的关键.25．（1）25；（2）8°48′；（3）．【解析】试题分析：（1）由C等级频数为15除以C等级所占的百分比60%，即可求得m的值；（2）首先求得B 等级的频数，继而求得B等级所在扇形的圆心角的大小；（3）首先根据题意画出树状图，然后由树状图求得所有等可能的结果与其中至少有一家是A等级的情况，再利用概率公式求解即可求得答案．试题解析：（1）∵C等级频数为15，占60%，∴m=15÷60%=25；（2）∵B等级频数为：25﹣2﹣15﹣6=2，∴B等级所在扇形的圆心角的大小为：×360°=28.8°=28°48′；（3）评估成绩不少于80分的连锁店中，有两家等级为A，有两家等级为B，画树状图得：∵共有12种等可能的结果，其中至少有一家是A等级的有10种情况，∴其中至少有一家是A等级的概率为：=．考点：频数（率）分布表；扇形统计图；列表法与树状图法．26．（1）答案见解析；（2）AB=1BE；（1）1．【解析】试题分析：（1）先判断出∠OCF+∠CFO=90°，再判断出∠OCF=∠ODF，即可得出结论；（2）先判断出∠BDE=∠A，进而得出△EBD∽△EDA，得出AE=2DE，DE=2BE，即可得出结论；（1）设BE=x，则DE=EF=2x，AB=1x，半径OD=32x，进而得出OE=1+2x，最后用勾股定理即可得出结论．试题解析：（1）证明：连结OD，如图．∵EF=ED，∴∠EFD=∠EDF．∵∠EFD=∠CFO，∴∠CFO=∠EDF．∵OC⊥OF，∴∠OCF+∠CFO=90°．∵OC=OD，∴∠OCF=∠ODF，∴∠ODC+∠EDF=90°，即∠ODE=90°，∴OD⊥DE．∵点D在⊙O上，∴DE是⊙O的切线；（2）线段AB、BE之间的数量关系为：AB=1BE．证明如下：∵AB为⊙O直径，∴∠ADB=90°，∴∠ADO=∠BDE．∵OA=OD，∴∠ADO=∠A，∴∠BDE=∠A，而∠BED=∠DEA，∴△EBD∽△EDA，∴DE BE BDAE DE AD==．∵Rt△ABD中，tanA=BDAD=12，∴DE BE AE DE==12，∴AE=2DE，DE=2BE，∴AE=4BE，∴AB=1BE；（1）设BE=x，则DE=EF=2x，AB=1x，半径OD=32x．∵OF=1，∴OE=1+2x．在Rt△ODE中，由勾股定理可得：（32x）2+（2x）2=（1+2x）2，∴x=﹣29（舍）或x=2，∴圆O的半径为1．点睛：本题是圆的综合题，主要考查了切线的判定和性质，等腰三角形的性质，锐角三角函数，相似三角形的判定和性质，勾股定理，判断出△EBD∽△EDA是解答本题的关键．27．①③④．【解析】试题分析：∵x=﹣1时y=﹣1，x=1时，y=3，x=1时，y=5，∴a-b1{35cca b c+=-=++=，解得a1{33ca=-==，∴y=﹣x2+3x+3，∴ac=﹣1×3=﹣3＜1，故①正确；对称轴为直线332(1)2x=-=⨯-，所以，当x＞32时，y的值随x值的增大而减小，故②错误；方程为﹣x2+2x+3=1，整理得，x2﹣2x﹣3=1，解得x1=﹣1，x2=3，所以，3是方程ax2+（b﹣1）x+c=1的一个根，正确，故③正确；﹣1＜x＜3时，ax2+（b﹣1）x+c＞1正确，故④正确；综上所述，结论正确的是①③④．故答案为①③④．【考点】二次函数的性质．。

2019-2020学年湛江二中港城中学高三英语上学期期中试卷及答案解析

2019-2020学年湛江二中港城中学高三英语上学期期中试卷及答案解析

2019-2020学年湛江二中港城中学高三英语上学期期中试卷及答案解析第一部分阅读（共两节，满分40分）第一节（共15小题；每小题2分，满分30分）阅读下列短文，从每题所给的A、B、C、D四个选项中选出最佳选项ABest language learning appsDuolingoThe app doesn't restrict how many languages you can try to learn at the same time. I use Duolingo to practice Spanish and German. In the app, you can access resources such as Duolingo Stories, which can allow you to check your comprehension skills as you go. I also subscribe to Premium for $10 per month which includes an ad-free experience and downloadable lessons.MemriseOne of my favorite parts of Memrise is its short videos about how real locals express different phrases in conversation. A few lessons are available for free daily, but the full program is accessible if you subscribe to Memrise Pro. There are three plans—one month for $9, a year for $30 or three months for $19.BusuuWhen you sign up for Busuu, you select the language you want to learn, and the app helps you determine how advanced you are with it and why you want to learn it, and to what level. From there, you set a daily study goal. Premium costs about $6 per month for a year.LiricaIf you listen to any song enough, you'll learn all the words through repetition, even if they're in a different language. But how do you figure out what they mean? This is where Lirica comes in. This app is unique in how it approaches teaching Spanish. Instead of traditional teaching methods for learning a language, Lirica uses popular music by Latin artists to help you learn the Spanish language and grammar. Lirica has a one-week free trial and then it's about $4 per month.1. Which app is best for learning multiple languages at a time?A. Lirica.B. Busuu.C. Memrise.D. Duolingo.2. How much should you pay for a quarterly subscription to Memrise Pro?A. $9.B. $19.C. $28.D. $30.3. What is special about Lirica?A. It offers a one-month free trial.B. It helps users set a daily study goal.C. It hires Latin artists to teach Spanish.D. It enables users to learn Spanish through music.BOne day when I was 5, my mother criticized me for not finishing my rice and I got angry. I wanted to play outside and not to be made to finish eating my old rice. In my angry motion to open the screen door (纱门) with my foot, I kicked back about a 12-inch part of the lower left hand corner of the new screen door. But I had no regret, for I was happy to be playing in the backyard with my toys.Today, I know if my child had done what I did, I would have criticized my child, and told him about how expensive this new screen door was, and I would have delivered a spanking (打屁股) for it. But my parents never said a word. They left the corner of the screen door pushed out, creating an opening, a crack in the defense against unwanted insects.For years, every time I saw that corner of the screen, it would remind me of my mistake from time to time. For years, I knew that everyone in my family would see that hole and remember who did it. For years, every time I saw a fly buzzing in the kitchen, I would wonder if it came in through the hole that I had created with my angry foot. I would wonder if my family members were thinking the same thing, silently blaming me every time a flying insectentered our home, making life more terrible for us all. My parents taught me a valuable lesson, one that a spanking or stern (严厉的) words perhaps could not deliver. Their silent punishment for what I had done delivered a hundred stern messages to me. Aboveall, it has helped me become a more patient person and not burst out so easily.4. When the author damaged the door, his parents _______.A. scolded him for what he had doneB. left the door unrepairedC. told him how expensive it wasD. gave him a spanking5. How did the author feel every time he saw the damaged door?A. He felt ashamed of his uncontrolled anger at that time.B. He found that his family members no longer liked him.C. He found it destroyed the happy atmosphere at his home.D. He felt he had to work hard to make up for (弥补) the damage.6. The experience may cause the author _______.A. to hide his anger away from othersB. not to go against his parents’ willC. to have a better control of himselfD. not to make mistakes in the future7. What of the following is the main idea of this passage?A. Adults should ignore their children’s bad behavior.B. Parents shouldn’t educate their children.C. What is the best way to become a more patient person?D. Silent punishment may have a better effect on educating people.CAmerican football was the fastest-growing sport for US young players last year, according to a survey sponsored by the sport's governing body.But it was the game's no tackle variety that showed the biggest increase－a finding that may reflect concerns about injury. In American football, a tackle (抢断球) refers to an attempt to stop an opponent by forcing them to the ground.The number of participants in football grew in 2015 while most other sport, except baseball, posted a decline, USA Football said on Monday, citing(引用) the findings of a survey of 30,000 children and teenagers.Participation in flag football (a no-tackle type of football) increased by 8.7 percent among children aged 6 to 14, while tackle football rose by 1.9 percent. For that age group, the only other sport that grew was baseball, with a 3. 3 percent increase.In the 15-to-18 age group, flag football rose by 10. 5 percent, while tackle grew by 2.5 percent.Basketball was the third, with a 1. 1 percent increase. Participation in all other sports declined.Tom Farrey, executive director of the Aspen Institute's Sports & Society Program, said he was surprised that flag football participation rose so much.“The trend suggests that parents aremarching to the beat of a different drummer, in pursuing flagas an alternative for their kids," he said.The findings come at a time of increasing concern about the risk associated with youth sports, particularly hockey (曲棍球) and football, where medical researchers have warned about the risk of concussions (damagesto the brain caused by violent blows to the head) and death linked to brain injury.USA Football, anIndianapolis,Indianabased nonprofit funded in part by the National Football League, believed that the increases resulted from better safety and health education."Football participation increases, even modest increases, may signal that programs such as our Heads Up Football program and practice guidelines are making a positive difference," said Scot Hallenbeck, USA Football chief executive, in a statement.Robert Cantu, aBostonUniversityneurosurgery professor and investigator at the school's chronic Traumatic Encephalopathy (CTE) Center said the increase in fag football participation signaled that more parents were directing children to a safe alternative8. What can we learn about the two age groups?A. Flag football grew the fastest in the 6-to-18 group.B. Tackle football grew he fastest in the 6-to-14 group.C. Participation in baseball declined the most in both groupsD. Participation in tackle football increased the most in both groups.9. The underlined part probably means ________.A working at a different paceB. behaving in a different wayC. ignoring the major differencesD. trying to accept different opinions10. The popularity of flag football is inked with the fact thatA. its rules have been adapted for young playersB. it receives more funds than other varietiesC. tackle football is an old-fashioned gameD. experts worry about children's safety11. What is the cause of football growth according to USA Football?A. Their safety programs are successful.B. More children show interest in the game.C. Football is less likely to cause concussions.D. There are different types of football to choose from.DFrom Mozart to Metallica, tons of people enjoy listening to various types of music while they paint, write, ordraw. Most believe that music helps increase creativity, but an international study conducted by English and Swedish researchers is challenging that view. The study results wereechoedby scientists fromLancasterUniversity, and theUniversityofGavle, saying their findings show music actually weakens creativity.To reach their conclusions, researchers had volunteers complete verbal problems designed to inspire creativity while sitting in a quiet room, and then again while music played in the background. They found that background music significantly weakened the volunteers’ ability to complete tasks connected with verbal creativity. The team also tested background noises like those commonly heard in a library, but found that such noises had no influence on subjects’ creativity.The tasks were simple word games. For example, volunteers were given three words, such as dress, rise, and flower. Then, they were asked to find a single word connected with all three that could be combined to form a common phrase or word. The single word, in this case, would be “sun” (sundress, sunrise, sunflower). Volunteers completed the tasks in either a quiet room, or while listening to two different types of music: rock music or light music“We found strong evidence of weakened performance when playing background music in comparison to quiet background conditions,” says co-author D. Neil McLatchie ofLancasterUniversity. He and his colleagues find that music negatively influences the verbal working memory processes of the brain, preventing creativity. Also, as far as the library background noises having seemingly no effect, the study’s authors believe that was the case because library noises create a “regular state” environment that doesn’t affect concentration.“To conclude, the findings here challenge the popular view that music increases creativity, and instead show that music, whatever type it is, is always a disadvantage for creative performance in problem solving,” the study reads.12. The underlined word in Paragraph 1 can be replaced by ________.A. challengedB. acceptedC. doubtedD. heard13. What were the volunteers asked to do in the study?A. To play music.B. To combine given words.C. To create new words.D. To connect words with music.14. What can we infer from the study?A. Quiet background inspires creativity best.B. Library noise does no harm to creativity.C. Music has a bad effect on language ability.D. Music types matter in creative performance.15. Which is the main idea of the passage?A. Quiet Environments Prevent Concentration.B. Background NoiseAffects Concentration.C. Composing Music Weakens Creativity.D. Listening to Music Reduces Creativity.第二节（共5小题；每小题2分，满分10分）阅读下面短文，从短文后的选项中选出可以填入空白处的最佳选项。

2019-2020学年湛江二中港城中学高三英语下学期期中试卷及答案

2019-2020学年湛江二中港城中学高三英语下学期期中试卷及答案

2019-2020学年湛江二中港城中学高三英语下学期期中试卷及答案第一部分阅读（共两节，满分40分）第一节（共15小题；每小题2分，满分30分）阅读下列短文，从每题所给的A、B、C、D四个选项中选出最佳选项AVienna Concerts 2021Every day, one to three dozen Vienna concerts are staged. You can use this checklist to find a fantastic Vienna concert that is worth its money.Vienna Chamber OrchestraThe Vienna Chamber Orchestra has existed for more than 70 years. The international reputation of the Vienna Chamber Orchestra is documented by worldwide tours. The length is 65 minutes.Date: 20th JuneLocation: Minoritenkirehe, Minoritenplatz 1, 1010 ViennaTickets: 30 Euros per adult and free admission for childrenVienna Philharmonic OrchestraIn 2021, famous conductor Gustavo Dudamel will lead the Vienna Philharmonic Orchestra. Expect an amazing show with top quality classical music and fireworks. The concert lasts one and a half hours. You have to arrive at least 20 minutes early to find a place to sit.Date: 4th and 5th OctoberLocation: Schonbrunn Palace, palace gardens, in front of Naptune fountain, Schonbrunner Schlossstrasse 47, 1130 Vienna.Tickets: 30 Euros（students, children and senior citizens will receive a 10% discount per ticket）Mozart Piano Sonatas（奏鸣曲）On Saturdays and Sundays, the St. Peter’s church opens its basement to a small group of Mozart fans. In simple but elegant surroundings, international pianists perform Mozart piano sonatas on a Steinway piano. The concerts start in the early evening and last 90 minutes.Date: throughout the yearLocation: St. Peter’s basement, Petersplatz 1, 1010 ViennaTickets: 29 Euros for adults and 16 Euros for children between 8 and 14（children below 8 can enterfor free.）Vivaldi: The Four SeasonsTo point out Vivaldi’s connection to Vienna, the Italian violinist lived in the city for some time, and eventually died there. Closer to where he was buried, the church St. Charles Borromeo regularly stages The Four Seasons, Vivaldi’s main work. The concerts start at 8:15 pm on weekends and last 60 minutes. People can arrive and enter anytime during the performance.Date: throughout the yearLocation: Church St. Charles Borromeo（Karlskirche）, Kreuzherrengase 1, 1040 ViennaTickets: 25 Euros for all ages（free cancellation 24 hours before the event）1.For a couple with their 10-year-old child, which is the cheapest?A.Mozart Piano Sonatas.B.Vienna Chamber Orchestra.C.Vivaldi: The Four Seasons.D.Vienna PhilharmonicOrchestra.2.What do the Vienna Philharmonic Orchestra and Mozart Piano Sonatas have in common?A.They last one and a half hours.B.They are held in closed surroundings.C.They offer a discount for students and the aged.D.They are suitable for people who prefer pop music.3.What can we know about the concert—The Four Seasons?A.It forbids people to enter after 8:15 pm.B.It describes Vivaldi’s stories related to Vienna.C.It allows you to return your ticket for free a day in advance.D.It was created by the Church St. Charles Borromeo to memorize Vivaldi.BNostalgia (怀旧) has become increasingly common in our current climate of accelerated, unexpected change. More and more Americans are turning back with longing towhat feels like simpler, sweeter times. They collect cassette tapes, manual typewriters even decades-old video games.Is it a mistake to get too obsessed with the past? Some psychologists warn that too much devotion to the so-called good old days is an escape from reality; it can indicate loneliness or that a person is having a difficult time coping in the present. Psychologist Stephanie Coontz argues that nostalgia distracts us from addressing the problems of modern life and contribute to anxiety, depression , insomnia etc.But new studies suggest that a modest dose of nostalgia is not only harmless, but actually beneficial. They suggest it helps strengthen our sense of identity and makes us feel more optimistic and inspired. It is also a toolfor self — discovery and memories are a psychological immune response that is triggered when you want to take a break from negativity. Interestingly, those happy memories can be particularly beneficial both to kids in their teens and to society's elders. Recalling our childhood reminds us of “the times when we were accepted and loved unconditionally," says Krystine Batcho, a psychologist. "That is such a powerfully comforting phenomenon, knowing that there was a time in life when we didn't have to earn our love." Nostalgia can transform even the most ordinary past into legends which warms the heart and the body. Let's not forget that nostalgia has been a source of inspiration to innumerable American writers. Mark Twain recalled his boyhood, writing, "after all these years, I can picture that old time to myself now, just as it was then：The white town drowsing in the sunshine of a summer's morning."So go ahead, daydream a little about your best childhood friend, your first car, a long - gone family pct. As Dr. Sedikidessays，"Nostalgia is ly central to human experience. "But at the same time, keep these words of wisdom from the great inventor Charles Kettering in mind as well："You can't have a better tomorrow if you are thinking about yesterday all the time. "34. What did some psychologists in paragraph 2 probably agree?A. Nostalgia will cause some mental problems.B. Nostalgia makes us devoted to the good old days.C. Nostalgia shows you are trying to get rid of loneliness.D. Nostalgia helps us cope with the difficult time we are going through.5. There are many benefits of nostalgia except ________A. It can enable us to know ourselves better.B. It can bring us some comfort when we recall.C. We are likely to gain attention if we recall the happy childhood.D. We can sometimes break away from negativity with happy memories.6. What will be talked about in the following paragraph?A. The bad influence of too much devotion to nostalgia.B. The reasons why we should avoid nostalgia.C. The bad memories that always stick around you.D. The great changes nostalgia will bring to you.7. What's the best title of the passage?A. We all have a soft spot for nostalgia.B. Nostalgia is actually good for you.C. Don't be carried away by nostalgia.D. There are many times when we like to recall.CTwenty years ago, I became involved in pet therapy(疗法) work with our Angel. As she matured and went through professional training, we realized that she would be good at this new job.Angel is ten now and works every week. She visits two hospitals providing day care for the elderly, and our library’s PAWS forReadingprogram. At the library, six to ten dogs lie on the floor, and the kids pick a book to read to a dog. After they finish, they get a card with the dog’s picture and history. Angel also helps out at a special-needs camp. She is so popular that everywhere we go people recognize her, especially the kids she has worked with.We have seen some very special things through our pet therapy work. I brought Angel to our local hospital to visit a woman who was completely unable to move the right side of her body from a stroke(中风). One day, my husband, Jack, got Angel up into a chair next to the woman’s bed, asking her if she wanted to give Angel a treat. She nodded. Angel gently took the treat. Then the woman raised her right hand and started petting Angel. Her friend couldn’t believe her eyes.After that, every time we saw the woman, she lifted her left hand. We’d tell her she had to use her right hand, and she would. Next, you’ll fall in love with this woman’s story of rearing her own Angel later in her family and why she calls it the best decision she ever made.8. Who is Angel?A. A pet trainer.B. A hospitalC. A therapy dog.D. The author’s kid.9. What does Angel usually do?A. Save seriously ill people.B. Pay visits to kids in hospital.C. Protect the elderly in their homes.D. Help children at a special camp.10. Why was the woman’s friend astonished?A The woman moved her right hand.B. The woman treated Angel.C. Angel helped the woman recover.D. Angel got along with the woman.11. What does the underlined word “rearing” in the last paragraph mean?A. Accompanying.B. Raising.C. Assisting.D. Training.DHave you ever done something that was really dangerous just because you thought it was safe？Maybe you did a dangerous trick on your bicycle or skateboard because you were wearing a helmet and thought you couldn’t get hurt. The psychology(心理) of this sort of behavior is called the Peltzman Effect, named after Sam Peltzman, professor of economics at the University of Chicago. Peltzman believes that those moments when people think they are the safest are the times when they act most dangerously.Peltzman said that people drove more dangerously when they wore seat belts(安全带) . Driving a large four-wheel drive vehicle has a similar effect on drivers’ behavior. Because drivers of large vehicles sit up higher and can see better, they feel they can make better judgments when they drive. They are better protected in accidents,so they act more dangerously. This makes driving morehazardousto other drivers.The Peltzman Effect isn’t just limited to driving. In 1972, the American Food and Drug Administration (FDA) passed a law requiring child safety caps on most medicine bottles. The safety caps were designed to prevent children from accidentally taking the medicine, especially painkillers such as aspirin. Requiring safety caps sounded like a great idea, but there was an unexpected side effect. Because the safety caps are so hardto take off, some people leave them off altogether．Worse, some parents leave the bottles where kids can reach them because they feel that it is safe because of the cap. A study on the Peltzman Effect showed that more than 3,500 children have been harmedby aspirin because of the safety caps.The Peltzman Effect describes how we’re likely to take more risks and act more dangerously when we feel safest. What’s more, the effects of these behaviors can be quite different from what we expect.12. What is the Peltzman Effect？A. People behave less safely when they feel safe．B. People feel safest when they are under protection．C. Something that seems dangerous turns out to be safe．D. People who act dangerously are likely to be together．13. What does the underlined word“hazardous”in Paragraph 2 mean？A. Interesting．B. Expensive．C. Dangerous．D. Important．14. Medicine bottles with safety caps ________．A. are required throughout the worldB. meet the demands of the Peltzman EffectC. sell well in the worldD. are not completely safe15. What would be the best title for the text？A. Unsafe Safety MeasuresB. Types of Decision MakingC. People’s Fear of Taking RisksD. Different Behaviors of People in Danger第二节（共5小题；每小题2分，满分10分）阅读下面短文，从短文后的选项中选出可以填入空白处的最佳选项。

2019-2020学年湛江二中港城中学高三英语期中考试试卷及答案

2019-2020学年湛江二中港城中学高三英语期中考试试卷及答案

2019-2020学年湛江二中港城中学高三英语期中考试试卷及答案第一部分阅读（共两节，满分40分）第一节（共15小题；每小题2分，满分30分）阅读下列短文，从每题所给的A、B、C、D四个选项中选出最佳选项ABest Places to Visit in JulyNorway's FjordsMost travelers prefer to visit Norway's famous fjords (峡湾) in July because Norway has about 23 hours of daylight, giving travelers lots of time to take in the spectacular views of blue water, glaciers and mountains. July is also whenNorway's weather is at its warmest, about18℃, so travelers might include a light sweater in their luggage.Bastille Day inParisJuly 14 is a national day celebrating independence to the French. July 14, 1789, is the day the French stormed the Bastille, aParisprison, and officially began the French Revolution, overthrowing a royal government that often threw people in prison there for no reason at all. While the day is marked all overFrance, the biggest celebration takes place inParis.Masai Mara National ReserveThe thrill of seeing millions of animals wander the plains inKenyais not easily forgotten. One of the most popular months to visit the Masai Mara is in July when the famous wildlife migration reaches the Masai Mara and zebras are at their highest number. The best times to view the animals inKenya's most popular game park are dawn and dusk.Running of the Bulls inPamplonaTravelers who pride themselves on being fast runners may want to head toPamplonain July for the San Femin Festival. A key part of this annual festival is the running of the bulls. Six bulls are released onto a narrow street fora half-mile run, with hundreds of runners seeing if they can run faster than the animals.1. What can visitors do inNorway's in July?A. Enjoy the impressive scenery.B. Swim and fish in the fjords.C. See daylight around the clock.D. Buy heavy sweaters to keep warm.2. Which of the following is of historical significance?A. San Fermin Festival.B. Bastille Day.C. Masai Mara National Reserve.D.Norway's Fjords.3. Where will visitors interested in wild animals go?A. Norway.B. Paris.C. Masai Mara.D.Pamplona.BImagine the feeling of swinging at a baseball going 100 miles per hour—without leaving your living room, or being in race car as it roars down the track, while you are sitting on the couch.These are just some of the ways that sports business leaders say virtual reality (VR) will revolutionize how people train for and experience sports. Virtual and augmented（增强的）realities are together known as mixed reality (MR). “American footballers are already using VR to better train their minds andread the field,” Ludden said. “This can allow players to perfect their skills without risking injury.”Canadian company D-BOX Technologies designs and produces moving seats found in cinema and theme parks. It is now moving into sports, and shows its Formula One (F1) racing simulator（模拟器）. The seats stimulate the force of gravity, speed and every shaking as Fl champion Lewis Hamilton zips around city streets.A simulation seat uses pre-programed data now. Someday, though, it could use real-time information sent by the car. “They couldbroadcast live content through a network in pop-up theaters around the world,” Ludden said. Say you want to experience the true stress of a batter being up against major-league baseball pitcher. “You can have a heartbeat added to the sensation on the seat and then you can feel it, boom, boom,” Maheu explained. “When he swings and hits the ball, you can have an impact.”One day, fans around the world could physically experience every game from their favorite player in real time. Ludden said that current and near-future technology could create “augmented stadiums” for live audiences. Panasonic launched its “Smart Venue” plans which included the overlaying of graphics, advertisements, player statistics and replays on the field of play at a pro football game. “If you are seated in the cheap seats, you can see this really useful.” “Fans may someday join in stadium wide games, using the field as a virtual gaming platform,” Ludden added.4. What does the underlined phrase “read the field” in paragraph 2 mean?A. Get off the playing field.B. Build up a football court.C. Judge the situation on the field.D. Ask players to play on the spot.5. What does Maheu think audiences can do in the future baseball game?A. Enjoy live content in any theater.B. Program the simulation seats in advance.C. Control the force and speed of the baseball.D. Experience the real time game with the player.6. What does Ludden mainly describe in the last paragraph?A. The origin of VR.B. A future stadium.C. An advertisement platform.D. The expectations of audiences.7. What is the main idea of the text?A. VR can improve players' skills for sports.B. VR increases fans' joy in the baseball game.C. VR can improve sports experience for players and fans.D. VR promises a new future for football players and games.CThe Chinese philosopher (哲学家) Confucius once said, “Time flows away like the water in the river.” This is especially true as the novel coronavirus pneumonia outbreak has affected millions of people in China, andthe whole nation has been working day and night to fight the epidemic.In late January, when an increasing number of people in Wuhan were suspected to be infected, and hospitals didn't have adequate beds for them, two special hospitals—Lei shenshan Hospital and Huo shenshan Hospital were built. These two makeshift (临时的) hospitals were built to treat pneumonia patients infected with the novel coronavirus.HuoshenshanHospitalhas 1,000 beds and covers 33,900 square meters, andLeishenshanHospitalhas 1,500 beds and a total area of about 79,000 square meters. More than 4,000 workers worked 24/7 in two shifts, and nearly 1,000 large-scale pieces of equipment and transport vehicles helped the project on site. The two hospitals were built in an amazingly short time. It only took 10 days for people to build Huo shenshan, and 14 days for Lei shenshan.This certainly wowed many people overseas. “It's incredible that two hospitals with 2,500 beds can be built in a short period. It's just hard to believe,” a foreigner named Stuart told People's Daily. In the meantime, Chinese companies have also taken actions quickly in this battle.“The automobile industry is highly industrialized with strong capabilities in comprehensive manufacturing, purchasing materials, production lines and output of technologies,” Shi Jianhua, deputy secretary-general of China Association of Automobile Manufacturers, told CCTV News. “In this special time, when the nation needs more masks, it's time for us to quickly respond and shoulder the social responsibilities.”Indeed, a fast response is crucial in any crisis. In this special time,Chinacan't afford to waste a second in the fight against the epidemic. After all, time equals life during this crisis.8. Confucius' saying “Time flows away like the water in the river.” is mentioned to ______.A. arouse readers' interest in the passage.B. introduce the subject of the passage.C. present the background information.D. stress the value of time in epidemic.9. What can we learn about Lei shenshan hospital and Huo shenshan hospital?A. They are new hospitals for health care inWuhan.B. They were built in minimal time.C. Over 4,000 workers worked continuously.D. Stuart found them too massive to believe.10. We can infer from Shi Jianhua's words that the automobile industry inChina______.A. had no medical supplies factories before.B. guarantees whoever in need enough masks.C. has capabilities to give timely response.D. has strong abilities in manufacturing.11. What does the passage mainly talk about?A. China fights epidemic against the clock.B. Twospecial hospitals were constructed.C. Chinese firms acted quickly and effectively.D. Time is crucial for people in overcoming crisis.DLarry was on another of his underwater expeditions(探险)but this time, it was different. He decided to take his daughter along with him. She was only ten years old. This would be her first trip with her father on what he had always been famous for.Larry first began diving when he was his daughter’s age. Similarly, his father had taken him along on one of his expeditions. Since then, he had never looked back. Larry started out by renting diving suits from the small diving shop just along the shore. He had hated them. They were either too big or too small. Then, there was the instructor. He gave him a short lesson before allowing him into the water with his father. He had made an exception. Larry would never have been able to go down without at least five hours of theory and another similar number of hours on practical lessons with a guide. Children of his age were not even allowed to dive.After the first expedition, Larry’s later diving adventures only got better and better. There was never a dull moment. In his black and blue suit and with an oxygen tank fastened on his back, Larry dived from boats into the middle of the ocean. Dangerous areas did not prevent him from continuing his search. Sometimes, he was limited to a cage underwater but that did not bother him. At least, he was still able to take photographs of the underwater creatures.Larry’s first expedition without his father was in the Cayman Islands. There were numerous diving spots in the area and Larry was determined to visit all of them .Fortunately for him, a man offered to take him around the different spots for rry didn’t even know what the time was, how many spots he dived into or how many photographs he had taken.The diving spots afforded such a wide range of fish and sea creatures that Larry saw more than thirty varieties of creatures.Larry looked at his daughter. She looked as excited as he had been when he was her age. He hoped she would be able to continue the family tradition. Already, she looked like she was much braver than had been then. This was the key to a successful underwater expedition.12. In what way was this expedition different for Larry?A. His daughter had grown up.B. He had become a famous diver.C. His father would dive with him.D. His daughter would dive with him.13. What can be inferred from Paragraph 2?A. Larry had some special right.B. Larry liked the rented diving suits.C. Divers had to buy diving equipment.D. Ten-year-old children were permitted to dive.14. What can be learned from the underlined sentence?A. Larry didn’t wear a watch.B. Larry was not good at math.C. Larry had a poor memory.D. Larry enjoyed the adventure.15. What did Larry expect his daughter to do?A. Become a successful diver.B. Make a good diving guide.C. Take a lot of photo underwater.D. Have longer hours of training.第二节（共5小题；每小题2分，满分10分）阅读下面短文，从短文后的选项中选出可以填入空白处的最佳选项。

2019-2020学年湛江二中港城中学高三英语月考试题及答案解析

2019-2020学年湛江二中港城中学高三英语月考试题及答案解析

2019-2020学年湛江二中港城中学高三英语月考试题及答案解析第一部分阅读（共两节，满分40分）第一节（共15小题；每小题2分，满分30分）阅读下列短文，从每题所给的A、B、C、D四个选项中选出最佳选项AF the Art World competition.Prize -The winner of each type will get the chance to display their artworks in a week-long exhibition inChelsea,New York..Eligibility - Open to artists all over the world..Entry Fee(参赛费)-$24 for a maximum of 3 submitted(提交的)photos..Date of Exhibition - From 25thApril to 2ndMay.F the Art World is an international art competition organized by which is quite unusual, compared to other competitions. The artworks are not judged on the basis of creativity and skill. Instead, they're judged by the depth of the subject matter. The subject this year is “A Competition About Change”, where artists can try and show how they'd like to change humanity in a good way.Notes*For this competition, there are three types for submissions, namely: street art, fine art, and digital art.*Each type will have a winner as chosen by the organizers and all the winners will have the wonderful chance to exhibit their works at the Unarthodox Gallery inNew Yorkin a week-long exhibition.*All the winners will also receive 100% of the sale price when any of their artworks are sold!Winners will also be displayed on the website and the entrants' artworks will also be displayed in the opening ceremony(仪式)as well.1.What is special about F the Art World Competition?AIt is free to attend.B.It lasts for over a week.C.It is open to artists inNew York.D.It centers on the depth of the artworks.2.What will the winners get?A.Prize money.B.A chance to visit an exhibition.C.A written judgement of their artworks.D.Money from the sale of their artworks.3.Where will the entrants' artworks be shown?A.In the street.B.In the opening ceremony.C.On the website.D.At the market.BSome years ago a young man applied to a large United States optical firm for a job as a lens designer. He apologized for lack of training, but on announcing that he owned two copies of the classic Conrady's Applied Optics and Optical Design, one for his office and a second for his bedside table, he was hired on the spot. Perhaps the story will be repeated some day with Buchdahl's Introduction to Hamiltonian Optics as a similar certificate of qualification.Hamiltonian theory describes with powerful generality the overall properties of optical systems considered as ‘black boxes’, although it does not describe the detailed structure needed to construct the systems and achieve these properties. Buchdahl's book is therefore on the subject of geometrical optics, but it is not about how to design lenses. It is, however a compact comprehensive account of the fundamentals of the theory written with the lens designer's needs very much in mind. Every lens designer worth his salt has at some time in his career attempted to apply the broad concepts of Hamiltonian optics to the solutions of practical problems. Success has been sufficiently rare that the theory, as such, has made little direct contribution to techniques for optical instrument design. The failures have been frustrating because of the obvious fundamental power of the theory and because of its conceptual elegance. The indirect effects have been large, however, both in contributing to an understanding of fundamental principles that govern the overall behavior of optical systems and in pointing the way to other, more practical, theoretical approaches.Buchdahl approaches the subject not only as a capable mathematical physicist, but as one who with a knowledge of practical optics has made a significant contribution to geometrical optical theory. Buchdahl's approach has, over the last decade, had a major impact on modern lens design with computers. Thus, he brings to this exposition of Hamiltonian optics a familiarity with practical optics not usually found in authors on this subject.The author claims his book to be non-mathematical, and indeed it might be so viewed by a professional mathematician. From the point of view of many physicists and engineers, it will appear to be quite mathematical. Moreover, this is a tightly written book. The subject matter is developed with precision, and the author expects the reader, at very point, to be master of the preceding exposition.4. Hamiltonian theory met with failures as a result of ______.A. newer finding related to the wave particle nature of lightB. very complicated concepts too difficult to understand by most lens designersC. too much mathematical detail in the theoryD. not enough practical information offered by the theory to allow for use by lens crafters5. The author of this passage implies that Introduction to Hamiltonian Optics is necessary to ______.A. the students who are major in mathematical geometryB. those who want to grasp the basic principles of optical systemsC. the lens designers who look for instructions on practical designsD. those who are interested in physics6. The article points out that the great benefits of Hamiltonian optics have been found is ______.A. indirect ways of learning mathematicsB. a fundamental power within the theoryC. the conceptual elegance of the theoryD. the practical applications of the theory in finding new approaches to old problems7. This passage is probably excerpted from ______.A. a review of a bookB. a chemistry textbookC. an optician's essayD. a general science textCIn 2015, a man named Nigel Richards memorized 386, 000 words in the entireFrench Scrabble Dictionaryin just nine weeks. However, he does not speak French. Richards’ impressive feat is a useful example to show how artificial intelligence works — real AI. Both of Richard and AI take in massive amounts of data to achieve goals with unlimited memory and superman accuracy in a certain field.The potential applications for AI are extremely exciting. Because AI canoutperformhumans at routine tasks — provided the task is in one field with a lot of data — it is technically capable of replacing hundreds of millions of white and blue collar jobs in the next 15 years or so.But not every job will be replaced by AI. In fact, four types of jobs are not at risk at all. First, there are creative jobs. AI needs to be given a goal to optimize. It cannot invent, like scientists, novelists and artists can. Second, the complex, strategic jobs — executives, diplomats, economists — go well beyond the AI limitation of single-field and Big Data. Then there are the as-yet-unknown jobs that will be created by AI.Are you worried that these three types of jobs won’t employ as many people as AI will replace? Not to worry, as the fourth type is much larger: jobs where emotions are needed, such as teachers, nannies and doctors. These jobs require compassion, trust and sympathy — which AI does not have. And even if AI tried to fake it, nobody would want a robot telling them they have cancer, or a robot to babysit their children.So there will still be jobs in the age of AI. The key then must be retraining the workforce so people can do them. This must be the responsibility not just of the government, which can provide funds, but also of corporations and those who benefit most.8. What is the main purpose of paragraph 1?A. To introduce the topic.B. To mention Nigel’s feat.C. To stress the importance of good memory.D. To suggest humans go beyond AI in memory.9. Which of the following best explains “outperform” underlined in paragraph 2?A. Be superior toB. Be equal toC. Be similar toD. Be related to10. Which of the following jobs is the most likely to be replaced?A. The writer.B. The shop assistant.C. The babysitter.D. The psychologist.11. What does the text suggest people do about job replacement of AI?A. Limit the application of AI to a certain degree.B. Get more support from the government.C. Apply for the donation from companies.D. Upgrade themselves all the time.DLast year, 138,000San Franciscoresidents used Airbnb, a popular app designed to connect home renters and travelers. It’s a striking number for a city with a population of about 850,000, and it was enough for Airbnb to win a major victory in local elections, asSan Franciscovoters struck down a debatable rule that would have placed time restrictions and other regulations on short-term rental services.The company fiercely opposed the measure, Proposition F, with a nearly $10 million advertising campaign. It also contacted its San Franciscan users with messages urging them to vote against Proposition F.Most people think of Airbnb as a kind of couch-surfing app. The service works for one-night stays on road trips and longer stays in cities, and it often has more competitive pricing than hotels. It’s a textbook example of the “sharing economy”, but not everyone is a fan.The app has had unintended consequences inSan Francisco. As the San Francisco Chronicle reported last year, a significant amount of renting on Airbnb is not in line with the company’s image: middle-class families putting up a spare room to help make ends meet. Some users have taken advantage of the service, using it to turn their multiple properties into vacation rentals or even full-time rentals. Backers of Proposition F argued that this trend takes spaces off the conventional, better-regulated housing market and contributes to rising costs.“The fact is, widespread abuse of short-term rentals is taking much needed housing off the market and harming our neighborhoods,” said ShareBetter SF, a group that supported Proposition F. Hotel unions have protested the company’s practices inSan Franciscoand other cities, saying that it creates an illegal hotel system.San Franciscois in the middle of a long-term, deeply rooted housing crisis that has seen the cost of living explode. Actually, explode is a generous term. The average monthly rent for an apartment is around $4, 000. Located on a narrow outcropping of land overlooking the bay,San Franciscosimply doesn’t have enough space to accommodate the massive inflow of young, high-salaried tech employees flocking toSilicon Valley.As the Los Angeles Times reported, someSan Franciscoresidents supported the measure simply because it seemed like a way to check a big corporation. Opponents of Proposition F countered that the housing crisis runs much deeper, and that passing the rule would have discouraged a popular service while doing little to solve the city’s existing problems.12. The intention of Proposition F is to ________.A. place time limits in local election.B. set limits on short-term rental.C. strike down a controversial rule.D. urge users to vote against Airbnb.13. What is the negative consequence of Airbnb onSan Francisco?A. It shrinks the living space of middle-class families.B. Users are taken advantage of by the service financially.C. It makes the house market more competitive.D. It indirectly leads to high house rental price.14. The housing crisis inSan Franciscoresults from ________.A. explosion of the living costB. its geographic characteristicsC. generosity of local enterprisesD. inflow of migrant population15. Theauthor’s attitude toward Proposition F is ________.A. objectiveB. supportiveC. negativeD. indifferent第二节（共5小题；每小题2分，满分10分）阅读下面短文，从短文后的选项中选出可以填入空白处的最佳选项。

2019-2020学年广东省湛江二中港城中学九年级(下)月考化学试卷(4月份)

2019-2020学年广东省湛江二中港城中学九年级(下)月考化学试卷(4月份)

2019-2020学年广东省湛江二中港城中学九年级（下）月考化学试卷（4月份）一、选择题（共15题，每题3分，共45分）1．（3分）下列关于酸和碱的叙述正确的是（）A．熟石灰能参与中和反应，可用于治疗胃酸过多B．浓硫酸可使有机物发生炭化现象，体现出吸水性C．浓盐酸瓶口可观察到白雾，具有挥发性D．烧碱易潮解，可用于二氧化碳的干燥2．（3分）下列说法正确的是（）A．维生素是人体重要的供能物质B．缺乏维生素C会引起坏血病C．微量元素对人体作用十分重要，必须大量服用D．幼儿患佝偻病的主要原因是缺碘3．（3分）小明发现自家农田里的作物叶色发黄，并且茎秆软弱容易倒伏，他应该施用下列化肥（）A．KNO3B．CO（NH2）2C．K2CO3D．Ca（PO3）44．（3分）下列物品所用材料不属于有机合成材料的是（）A．汽车橡胶轮胎B．自行车合金车架C．雨衣涤纶面料D．食品包装塑料袋5．（3分）以科学原理和实验事实为依据进行推理是学习化学的一种重要方法。

下列推理得出的相关结论合理的是（）A．碱溶液的pH都大于7，pH大于7的溶液一定是碱溶液B．化合物是由不同种元素组成的纯净物，所以只含一种元素的物质一定不是化合物C．中和反应生成盐和水，所以生成盐和水的反应一定是中和反应D．金刚石和石墨都是由碳元素组成的单质，所以它们的性质完全相同6．（3分）下列对化学物质进行的分类，其中正确的是（）A．冰、干冰、可燃冰都是氧化物B．焊锡、不锈钢、黄铜都是合金C．复合肥：KNO3、NH4H2PO4、NH4ClD．羊毛、塑料、腈纶都是合成材料7．（3分）在日常生活中，下列做法不正确的是（）A．熟石灰可以改良酸性土壤，但不能和氮肥混合使用B．可以在胃镜检查中，服用含有硫酸钡的钡粥C．用加洗涤剂的水除去餐具表面的油污D．为了给人体补充铁元素，在麦片中加入少量极细的还原铁粉8．（3分）对化学反应A+B═C+D的下列说法中正确的是（）A．若A是稀硫酸，则生成物质中一定有水B．若C、D是盐和水，则A、B一定是酸和碱C．若A是可溶性碱，B是可溶性盐，则C、D不可能是两种沉淀D．若A、B、C、D都是化合物，则该反应不一定是复分解反应9．（3分）甲、乙、丙三种物质的溶解度曲线如图所示。

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湛江二中港城中学2019-2020学年度第二学期九年级英语4月月考考试时间：90分钟满分：120分命题人:cwx一、听力理解（本大题分为A、B、C、D四部分，共30小题，每小题1分，共30分。

）A.听单句（本题有5小题，每小题1分，共5分）根据所听句子的内容和所提的问题，选择符合题意的图画回答问题。

每小题听一遍。

（）1.What is the girl talking about?A B C( )2.What is the boy’s brother doing now?A B C( )3.What is the shirt made of?A B C( )4.How should we greet Tina?A B C( )5.What did the girl have for lunch today?A B DB.听对话(本题有10小题，每小题1分，共10分)根据所听内容，回答每段对话后面的问题，在每小题所给的三个选项中选出一个最佳的答案。

每段对话听两遍。

听第一段对话，回答第6小题( )6.Why doesn’t the man tell the woman the way?A.Because he is too busy.B,Because he doesn’t know the way.C.Because he doesn’t like helping other.听第二段对话，回答第7小题( )7.What does the girl mean?A.She doesn’t like the hamburger.B.The hamburger tastes great.C.The hamburger tastes bad.听第三段对话，回答第8小题( )8.What colour is the sweater?A.It’s yellowB.It’s greenC.It’s purple听第四段对话，回答第9小题( )9.Who is the woman speaking to?A.A reporterB.B teacherC.A teacher听第五段对话，回答第10小题( )10.How did Bob feel when he met Sarah Brown?A.He felt excited.B.He felt nervous.C.He felt disappointed.听第六段对话，回答第11-12小题( ).11.How does the girl feel when she speaks to strangers in English?A.HappyB.NervousC.Sleepy.( )12.How often does the boy go to the English club?A.Every dayB.Once a weekC.Twice a week.听第七段对话，回答第13-15小题( )13.Why did the organization start such a day?A.To advertise an organization.B.To encourage a good sleep.C.To educate people on cellphones.( )14.What does the man advise the woman to do?A.To avoid reading before sleeping.B.To see a doctor the day after tomorrow.C.To stop using the cellphone before sleeping.( )15.What day is it today?A.WednesdayB.ThursdayC.FridayC.听独白（本题有10小题，每小题1分，共10分）根据所听内容，在每小题所给的三个选项中，选出一个能完成句子的最佳答案。

独白听两遍。

听第一篇独白，回答16-20小题。

( )16.The three young people are talking about their____A.future lifeB.future jobsC.future family( )17.Judy wants to be a(n)_____A.pilotB.inventorC.reporter( )18.Paul is going to____for his dream.A.study Chinese hardB.train is mindC.learn something about flying.( )19.Tony wishes to make our world better by_____.A.writing more articlesB.making more friendsC.inventing more new things( )20.Tony is going to learn____well.A.math and scienceB.physics and mathC.English and science听第二篇独白，回答21-25小题。

( )21.Wu Yifan and his family moved to Canada in_____.A.1990B.2000C.2008( )22.Wu Yifan joined EXO when he was____years old.A.15B.17C.22( )23.In 2014,Wu Yifan_____.A.moved to South KoreaB.got back to China.C.studied in Canada.( )24.There are_____films mentioned in the listening.A.4B.3C.2( )25.It’s clear that Wu Yifan has great talent in_______.A.singing and actingB.Singing and actingC.dancing and rappingD.听填信息（本题共有5小题，每小题1分，共5分）你将听到一篇短文，请你根据所听内容填写下面的信息卡。

短文听两遍。

二、语法选择（本大题共有10小题，每小题1分，共10分）阅读下面短文，按照句子结构的语法性和上下文连贯的要求，从各题所给的A、B、C 和D 项中选出最佳选项。

When I was a kid, watermelons were expensive. One of my father’s friends, Bernie, 31 a rich businessman. He had a large store.Every summer, 32 the first watermelons arrived,Bernie would call us. Dad and I would go to Bernie’ place. We would sit on the edge of the dock (码头), feet dangling (悬摆), and get ready for a big meal.Bernie would use 33 knife to cut our first watermelon, give each of us a big piece and sit down next to us. We were so happy that we often buried our faces in the watermelon, eating only the heart —34 and the juiciest part.Bernie was my father’s idea of a rich man. I always thought it was because he was such 35 successful businessman. Years later, I realized that it was not Bernie’s wealth itself but his way of dealing with it that my father liked. Bernie knew 36 to stop working, get together with friends and eat only the heart of the watermelon.What I learned 37 Bernie is that being rich is a state of mind. Some of us, no matter how much money we have, will 38 be free enough to eat only the heart of the watermelon. If you don’t take the time to dangle your feet over the dock and enjoy life’s small pleasure, your work is probably hurting your life.For many years, I forgot the lesson I had learned as a kid on the loading dock. I was busy 39 money all the time.Well, I’ve relearned it. I hope that I40 time left to enjoy the success of others and to take pleasure during the day.( )31.A.is B.was C.are D.were( )32.A.unless B.though C.since D.when( )33.A.he B.him C.his D.himself( )34.A.red B.redder C.the redder D.the reddest( )35.A.a B.an C.the D.不填( ).37.A.form B.for C.with D.at( )38.A.always B.often C.ever D.never( )39.A.making B.to making C.to make D.make( )40.A.have B.has C.had D.was having三、完型填空（本大题有10小题，每小题1分，共10分）通读下面短文，掌握其大意，然后再每小题所给的四个选项中。

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