7A 易错题汇编单选专项(附答案)

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七年级下册数学易错题整理附答案(超好)

七年级数学下易错题练习答案第五章相交线与平行线1．如图，将一张含有30°角的三角形纸片的两个顶点叠放在矩形的两条对边上，若∠2=44°，则∠1的大小为（）A．14° B．16° C．90°﹣α D．α﹣44°【解答】解：如图，∵矩形的对边平行，∴∠2=∠3=44°，根据三角形外角性质，可得∠3=∠1+30°，∴∠1=44°﹣30°=14°，故选：A．2．如图，有一块含有30°角的直角三角板的两个顶点放在直尺的对边上．如果∠2=44°，那么∠1的度数是（）A．14° B．15° C．16° D．17°【解答】解：如图，∵∠ABC=60°，∠2=44°，∴∠EBC=16°，∵BE∥CD，∴∠1=∠EBC=16°，故选：C．3．如图，直线a∥b，直线c分别交a，b于点A，C，∠BAC的平分线交直线b于点D，若∠1=50°，则∠2的度数是（）A．50°B．70° C．80° D．110°【解答】∴∠2=180°﹣50°﹣50°=80°．故选：C．4．如图把一个直角三角尺的直角顶点放在直尺的一边上，若∠1=50°，则∠2=（）A．20°B．30° C．40° D．50°【解答】解：∵直尺对边互相平行，故选：C．∴∠3=∠1=50°，∴∠2=180°﹣50°﹣90°=40°．5．如图，将矩形ABCD沿GH折叠，点C落在点Q处，点D落在AB边上的点E处，若∠AGE=32°，则∠GHC等于（）A．112°B．110°C．108°D．106°【解答】解：∵∠AGE=32°，∴∠DGE=148°，由折叠可得，∠DGH=∠DGE=74°，∵AD∥BC，∴∠GHC=180°﹣∠DGH=106°，故选：D．6．如图，AB∥CD，点E在线段BC上，∠CDE=∠CED．若∠ABC=30°，则∠D为（）A．85°B．75° C．60° D．30°【解答】故选：B．7．如图，将矩形ABCD沿对角线BD折叠，点C落在点E处，BE交AD于点F，已知∠BDC=62°，则∠DFE的度数为（）A．31° B．28° C．62° D．56°【解答】解：∵四边形ABCD为矩形，∴AD∥BC，∠ADC=90°，∵∠FDB=90°﹣∠BDC=90°﹣62°=28°，∵AD∥BC，∴∠CBD=∠FDB=28°，∵矩形ABCD沿对角线BD折叠，∴∠FBD=∠CBD=28°，∴∠DFE=∠FBD+∠FDB=28°+28°=56°．故选：D．8．如图，在平行线l1、l2之间放置一块直角三角板，三角板的锐角顶点A，B分别在直线l1、l2上，若∠l=65°，则∠2的度数是（）A．25° B．35° C．45° D．65°【解答】解：如图，过点C作CD∥a，则∠1=∠ACD．∴∠1+∠2=90°，又∵∠1=65°，∴∠2=25°．故选：A．9．如果∠A和∠B的两边分别平行，那么∠A和∠B的关系是（）A．相等B．互余或互补C．互补D．相等或互补二、填空题1.如图，把一张长方形的纸片按如图所示的方式折叠，EM 、FM 为折痕，折叠后的C 点落在B ′M 或B ′M 的延长线上，则∠EMF = 90°2．如图，把长方形ABCD 沿EF 对折，若∠1=500，则∠AEF= 115度.3 将长方形纸片ABCD 沿过A 点的直线折叠，折痕为线段AE ，得到图8所示的图形，已知∠CED ′=50º，则∠AED = 65 度.4、改写成如果…那么…形式1、改写：如果三个角是一个三角形的内角，那么这三个角的和是180°。

(易错题精选)初中数学函数基础知识易错题汇编及解析(1)

（易错题精选）初中数学函数基础知识易错题汇编及解析(1)一、选择题1．如图，点M 为▱ABCD 的边AB 上一动点，过点M 作直线l 垂直于AB ，且直线l 与▱ABCD 的另一边交于点N ．当点M 从A→B 匀速运动时，设点M 的运动时间为t ，△AMN 的面积为S ，能大致反映S 与t 函数关系的图象是（）A ．B ．C ．D ．【答案】C【解析】分析：本题需要分两种情况来进行计算得出函数解析式，即当点N 和点D 重合之前以及点M 和点B 重合之前，根据题意得出函数解析式．详解：假设当∠A=45°时，2AB=4，则MN=t ，当0≤t≤2时，AM=MN=t ，则S=212t ，为二次函数；当2≤t≤4时，S=t ，为一次函数，故选C ．点睛：本题主要考查的就是函数图像的实际应用问题，属于中等难度题型．解答这个问题的关键就是得出函数关系式．2．下列说法：①函数6y x =-x 的取值范围是6x >；②对角线相等的四边形是矩形；③正六边形的中心角为60︒；④对角线互相平分且相等的四边形是菱形；⑤计算92|-的结果为7：⑥相等的圆心角所对的弧相等；1227理数．其中正确的个数有（）A ．1个B ．2个C ．3个D ．4个【答案】B【解析】【分析】根据正多边形和圆，无理数的定义，二次根式的加减运算，菱形的判定，矩形的判定，函数自变量的取值范围解答即可．【详解】解：①函数6y x =-的自变量x 的取值范围是6x ≥；故错误；②对角线相等且互相平分的四边形是矩形；故错误；③正六边形的中心角为60°；故正确；④对角线互相平分且垂直的四边形是菱形；故错误；⑤计算|9-2|的结果为1；故错误；⑥同圆或等圆中，相等的圆心角所对的弧相等；故错误；⑦122723333-=-=-是无理数；故正确．故选：B ．【点睛】本题考查了正多边形和圆，无理数的定义，二次根式的加减运算，菱形的判定，矩形的判定，函数自变量的取值范围，熟练掌握各知识点是解题的关键．3．如图，在边长为3的菱形ABCD 中，点P 从A 点出发，沿A→B→C→D 运动，速度为每秒3个单位；点Q 同时从A 点出发，沿A→D 运动，速度为每秒1个单位，则APQ ∆的面积S 关于时间t 的函数图象大致为（）A ．B ．C ．D ．【答案】D【解析】【分析】根据动点的运动过程分三种情况进行讨论解答即可．【详解】解：根据题意可知：3AP t =，AQ t =，当03t <<时，2133sin sin 22S t t A t A =⋅⋅=⋅ 0sin 1A <<∴此函数图象是开口向上的抛物线；当36t <<时，133sin sin 22S t A t A =⋅⋅=⋅ ∴此时函数图象是过一、三象限的一次函数；当69t <<时，2139(93)sin ()sin 222S t t A t t A =⋅⋅-=-+． ∴此时函数图象是开口向下的抛物线．所以符号题意的图象大致为D ．故选：D ．【点睛】本题考查了动点问题的函数图象，解决本题的关键是根据动点运动过程表示出函数解析式．4．函数2x y x =-中自变量x 的取值范围是（） A ．x≠2B ．x≥2C ．x≤2D ．x ＞2【答案】A【解析】【分析】根据分式的意义，进行求解即可．【详解】解：根据分式的意义得2-x≠0，解得x≠2故选：A【点睛】本题考查了求自变量的取值范围，函数自变量的范围一般从几个方面考虑：（1）当函数表达式是整式时，自变量可取全体实数；（2）当函数表达式是分式时，考虑分式的分母不能为0；（3）当函数表达式是二次根式时，被开方数为非负数．5．若A(﹣3，y 1)、B(0，y 2)、C(2，y 3)为二次函数y ＝（x+1）2+1的图象上的三点，则y 1、y 2、y 3的大小关系是（）A ．y 1＜y 2＜y 3B ．y 2＜y 1＜y 3C ．y 3＜y 1＜y 2D ．y 1＜y 3＜y 2【答案】B【解析】【分析】把三个点的坐标代入二次函数解析式分别计算出则y1、y2、y3的值，然后进行大小比较．【详解】解：∵A（﹣3，y1）、B（0，y2）、C（2，y3）为二次函数y＝（x+1）2+1的图象上的三点，∴y1＝（﹣3+1）2+1＝5，y2＝（0+1）2+1＝2，y3＝（2+1）2+1＝10，∴y2＜y1＜y3．故选：B．【点睛】本题考查了比较函数值大小的问题，掌握二次函数的性质、代入法是解题的关键．6．一个装有进水管和出水管的容器，从某时刻开始的4分钟内只进水不出水，在随后的8分钟内既进水又出水，接着关闭进水管直到容器内的水放完.假设每分钟的进水量和出水量是两个常数，容器内的水量y（单位：升）与时间x（单位：分钟）之间的部分关系如图象所示，从开始进水到把水放完需要多少分钟．（）A．20 B．24 C．18 D．16【答案】A【解析】【分析】先根据函数图象求出进水管每分钟的进水量和出水管每分钟的出水量，然后再求出关闭进水管后出水管放完水的时间即可解决问题．【详解】解：由函数图象得：进水管每分钟的进水量为：20÷4＝5升，设出水管每分钟的出水量为a升，由函数图象，得：302058a--=，解得：a＝154，∴关闭进水管后出水管放完水的时间为：30÷154＝8分钟，∴从开始进水到把水放完需要12＋8＝20分钟，故选：A ．【点睛】本题考查从函数的图象获取信息和用一元一次方程解决实际问题，正确理解函数图象横纵坐标表示的意义，理解问题的过程，能够通过图象列出算式和方程是解题的关键．7．如图，在矩形ABCD 中，2AB =，3BC =，动点P 沿折线BCD 从点B 开始运动到点D ．设运动的路程为x ，ADP ∆的面积为y ，那么y 与x 之间的函数关系的图象大致是（）A ．B ．C ．D ．【答案】D【解析】【分析】由题意当03x ≤≤时，3y =，当35x <<时，()131535222y x x =⨯⨯-=-+，由此即可判断．【详解】由题意当03x ≤≤时，3y =，当35x <<时，()131535222y x x =⨯⨯-=-+，故选D ．【点睛】本题考查动点问题的函数图象，解题的关键是理解题意，学会用分类讨论是扇形思考问题．8．如图，2020D 次哈尔滨至幸福镇的动车需要匀速通过一条隧道（隧道长大于火车长），火车在隧道内的长度与火车进入隧道的时间x 之间的关系用图象描述大致是（）A ．B ．C ．D ．【答案】A【解析】【分析】火车通过隧道分为3个过程：逐渐进入隧道，完全进入隧道并在其中行驶，逐渐出隧道【详解】火车在逐渐进入隧道的过程中，火车在隧道内的长度逐渐增加；火车完全进入隧道后，还在隧道内行驶一段时间，因此在隧道内的长度是火车长，且保持一段时间不变；火车在逐渐出隧道的过程中，火车在隧道内的长度逐渐减少；符合上述分析过程的为：A故选：A【点睛】本题考查函数图像在生活中的应用，解题关键是分析事件变化的过程，并能够匹配对应函数图像变化9．如图，在矩形ABCD 中，AB 4=，BC 6=，当直角三角板MPN 的直角顶点P 在BC 边上移动时，直角边MP 始终经过点A ，设直角三角板的另一直角边PN 与CD 相交于点Q.BP x =，CQ y =，那么y 与x 之间的函数图象大致是( )A ．B ．C．D．【答案】D【解析】试题解析：设BP=x，CQ=y，则AP2=42+x2，PQ2=（6-x）2+y2，AQ2=（4-y）2+62；∵△APQ为直角三角形，∴AP2+PQ2=AQ2，即42+x2+（6-x）2+y2=（4-y）2+62，化简得：y=−14x2+32x整理得：y=−14(x−3)2+94根据函数关系式可看出D中的函数图象与之对应．故选D．【点睛】本题考查的是动点变化时，两线段对应的变化关系，重点是找出等量关系，即直角三角形中的勾股定理．10．下列各曲线中，表示y是x的函数的是（）A．B．C．D．【答案】B【解析】【分析】根据函数的意义即可求出答案．【详解】解：根据函数的意义可知：对于自变量x的任何值，y都有唯一的值与之相对应，所以B 正确．故选：B．【点睛】此题考查函数图象的概念．解题关键在于要能根据函数图象的性质和图象上的数据分析得出函数的类型和所需要的条件，结合实际意义得到正确的结论．函数的意义反映在图象上简单的判断方法是：做垂直x轴的直线在左右平移的过程中与函数图象只会有一个交点．11．如图，点P是▱ABCD边上的一动点，E是AD的中点，点P沿E→D→C→B的路径移动，设P点经过的路径长为x，△BAP的面积是y，则下列能大致反映y与x的函数关系的图象是（）A． B．C．D．【答案】D【解析】【分析】根据题意分类讨论，随着点P位置的变化，△BAP的面积的变化趋势．【详解】通过已知条件可知，当点P与点E重合时，△BAP的面积大于0；当点P在AD边上运动时，△BAP的底边AB不变，则其面积是x的一次函数，面积随x增大而增大；当P在DC 边上运动时，由同底等高的三角形面积不变，△BAP面积保持不变；当点P带CB边上运动时，△BAP的底边AB不变，则其面积是x的一次函数，面积随x增大而减小；故选D．【点睛】本题以动点问题为背景，考查了分类讨论的数学思想以及函数图象的变化规律．12．如图1所示，A，B两地相距60km，甲、乙分别从A，B两地出发，相向而行，图2中的1l，2l分别表示甲、乙离B地的距离y（km）与甲出发后所用的时间x（h）的函数关系．以下结论正确的是( )A ．甲的速度为20km/hB ．甲和乙同时出发C ．甲出发1.4h 时与乙相遇D ．乙出发3.5h 时到达A 地【答案】C【解析】【分析】根据题意结合图象即可得出甲的速度；根据图象即可得出甲比乙早出发0.5小时；根据两条线段的交点即可得出相遇的时间；根据图形即可得出乙出发3h 时到达A 地．【详解】解：A ．甲的速度为：60÷2=30，故A 错误；B ．根据图象即可得出甲比乙早出发0.5小时，故B 错误；C ．设1l 对应的函数解析式为111y k x b =+，所以：1116020b k b =⎧⎨+=⎩，解得113060k b =-⎧⎨=⎩ 即1l 对应的函数解析式为13060y x =-+；设2l 对应的函数解析式为222y k x b =+，所以：22220.503.560k b k b +=⎧⎨+=⎩，解得 222010k b =⎧⎨=-⎩ 即2l 对应的函数解析式为22010y x =-，所以：30602010y x y x =-+⎧⎨=-⎩，解得 1.418x y =⎧⎨=⎩∴点A 的实际意义是在甲出发1.4小时时，甲乙两车相遇，故本选项符合题意； D ．根据图形即可得出乙出发3h 时到达A 地，故D 错误．故选：C ．【点睛】本题考查一次函数的应用，解答本题的关键是明确题意，找出所求问题需要的条件，利用一次函数的性质和数形结合的思想解答．13．甲、乙两同学骑自行车从A 地沿同一条路到B 地，已知乙比甲先出发，他们离出发地的距离S （km ）和骑行时间t （h ）之间的函数关系如图所示，给出下列说法：①他们都骑行了20km ；②乙在途中停留了0.5h ；③甲、乙两人同时到达目的地；④相遇后，甲的速度小于乙的速度．根据图象信息，以上说法正确的有（）A ．1个B ．2个C ．3个D ．4个【答案】B【解析】试题分析：根据图象上特殊点的坐标和实际意义即可作出判断．由图可获取的信息是：他们都骑行了20km ；乙在途中停留了0.5h ；相遇后，甲的速度＞乙的速度，所以甲比乙早0.5小时到达目的地，所以（1）（2）正确．故选B ．考点：本题考查的是学生从图象中读取信息的数形结合能力点评：同学们要注意分析其中的“关键点”，还要善于分析各图象的变化趋势．14．甲乙两同学同时从400m 环形跑道上的同一点出发，同向而行，甲的速度为6/m s ，乙的速度为4/m s ，设经过xs 后，跑道上两人的距离（较短部分）为ym ，则y 与x 0300x ≤≤之间的关系可用图像表示为（）A ．B ．C ．D ．【答案】C【解析】【分析】根据同向而行，二人的速度差为642/m s -=，二人间的最长距离为200，最短距离为0，从而可以解答本题．【详解】二人速度差为642/m s -=，100秒时，二人相距2×100=200米，200秒时，二人相距2×200=400米，较短部分的长度为0，300秒时，二人相距2×300=600米，即甲超过乙600-400=200米．∴()201004002(100200)2400(200300)x xy x xx x⎧≤≤⎪=-<≤⎨⎪-<≤⎩，函数图象均为线段，只有C选项符合题意．故选：C．【点睛】本题考查了利用函数的图象解决实际问题以及动点问题的函数图象，正确理解函数图象表示的意义，理解问题的过程，就能够通过图象得到函数问题的相应解决．15．“同辞家门赴车站，别时叮咛语千万，学子满载信心去，老父怀抱希望还．”如果用纵轴y表示父亲和学子在行进中离家的距离，横t表示离家的时间，下面与上述诗意大致相吻合的图象是()A ．B ．C ．D ．【答案】B【解析】【分析】首先正确理解小诗的含义，然后再根据时间与离家的距离关系找出函数图象．【详解】解：同辞家门赴车站，父亲和孩子的函数图象在一开始的时候应该一样，别时叮咛语千万，时间在加长，路程不变，学子满载信心去，学子离家越来越远，老父怀抱希望还，父亲回家离家越来越近，故选：B．【点睛】此题主要考查了函数图象，首先应理解函数图象的横轴和纵轴表示的量，再根据实际情况来判断函数图象．16．下列图象中不是表示函数图象的是（）A．B．C．D．【答案】C【解析】【分析】根据函数的定义可知，满足对于x的每一个取值，y都有唯一确定的值与之对应关系，据此即可确定函数的个数．【详解】解：A选项：满足对于x的每一个取值，y都有唯一确定的值与之对应关系，故A是函数；B选项：满足对于x的每一个取值，y都有唯一确定的值与之对应关系，故B是函数；C选项：不满足对于x的每一个取值，y都有唯一确定的值与之对应关系，故C不是函数；D选项：满足对于x的每一个取值，y都有唯一确定的值与之对应关系，故D是函数，故选：C．【点睛】主要考查了函数的定义．函数的定义：在一个变化过程中，有两个变量x，y，对于x的每一个取值，y都有唯一确定的值与之对应，则y是x的函数，x叫自变量．17．如图1．已知正△ABC中，E，F，G分别是AB，BC，CA上的点，且AE＝BF＝CG，设△EFG的面积为y，AE的长为x，y关于x的函数图象如图2，则△EFG的最小面积为（）A 3B3C．2 D3【答案】A 【解析】【分析】本题根据图2判断△EFG 的面积y 最小时和最大时分别对应的x 值，从而确定AB ，EG 的长度，求出等边三角形EFG 的最小面积．【详解】由图2可知，x ＝2时△EFG 的面积y 最大，此时E 与B 重合，所以AB ＝2，∴等边三角形ABC∴等边三角形ABC由图2可知，x ＝1时△EFG 的面积y 最小，此时AE ＝AG ＝CG ＝CF ＝BG ＝BE ，显然△EGF 是等边三角形且边长为1，所以△EGF 的面积为4，故选A ．【点睛】本题是运动型综合题，考查了动点问题的函数图象等边三角形等知识点．解题关键是深刻理解动点的函数图象，了解图象中关键点所代表的实际意义，理解动点的完整运动过程．18．已知：[]x 表示不超过x 的最大整数．例：[]3.93=，[]1.82-=-．记1()44k k f k +⎡⎤⎡⎤=-⎢⎥⎢⎥⎣⎦⎣⎦（k 是正整数）．例：3133144()f ⎡⎤⎡⎤+=-=⎢⎥⎢⎥⎣⎦⎣⎦．则下列结论正确的个数是（）（1）()10f =；（2）()()4f k f k +=；（3）()()1f k f k +≥；（4）()0f k =或1．A ．1个B ．2个C ．3个D ．4个【答案】C【解析】【分析】根据题中所给的定义，依次作出判断即可．【详解】解：111(1)00044f +⎡⎤⎡⎤=-=-=⎢⎥⎢⎥⎣⎦⎣⎦，正确； 41411(4)11()444444k k k k k k f k f k +++++⎡⎤⎡⎤⎡⎤⎡⎤⎡⎤⎡⎤+=-=+-+=-=⎢⎥⎢⎥⎢⎥⎢⎥⎢⎥⎢⎥⎣⎦⎣⎦⎣⎦⎣⎦⎣⎦⎣⎦，正确；当k=3时，414(31)11044f +⎡⎤⎡⎤+=-=-=⎢⎥⎢⎥⎣⎦⎣⎦，而(3)1f =，错误；当k=3+4n （n 为自然数）时，f （k ）=1，当k 为其它的正整数时，f （k ）=0，正确；正确的有3个，故选：C ．【点睛】本题考查新定义下的实数运算，函数值．能理解题中新的定义，并根据题中的定义进行计算是解决此题的关键．19．如图1，点F 从菱形ABCD 的项点A 出发，沿A －D －B 以1cm/s 的速度匀速运动到点B ．图2是点F 运动时，△FBC 的面积y (m 2)随时间x (s)变化的关系图象，则a 的值为( )A ．5B ．2C ．52D ．5【答案】C【解析】【分析】过点D 作DE BC ⊥于点E 由图象可知，点F 由点A 到点D 用时为as ，FBC ∆的面积为2acm ．求出DE=2，再由图像得5BD =BE=1，再在DEC Rt △根据勾股定理构造方程，即可求解．【详解】解：过点D 作DE BC ⊥于点E由图象可知，点F 由点A 到点D 用时为as ，FBC ∆的面积为2acm ．AD BC a ∴== ∴12DE AD a =g 2DE ∴=由图像得，当点F 从D 到B 时，用5s5BD ∴=Rt DBE V 中，2222(5)21BE BD DE --=∵四边形ABCD 是菱形，1EC a ∴=-，DC a =DEC Rt △中，2222(1)a a =+- 解得52a =故选：C ．【点睛】本题综合考查了菱形性质和一次函数图象性质，要注意函数图象变化与动点位置之间的关系，解答此题关键根据图像关键点确定菱形的相关数据．20．小明从家骑车上学，先匀速上坡到达A 地后再匀速下坡到达学校，所用的时间与路程如图所示，如果返回时，上、下坡速度仍然保持不变，那么他从学校回到家需要的时间是( )A ．9分钟B ．12分钟C ．8分钟D ．10分钟【答案】B【解析】【分析】先根据图形，得到上坡、下坡的时间和距离，然后分别求出上、下坡的速度，最后计算返回家的时间【详解】根据图形得，从家到学校：上坡距离为1km ，用时5min ，下坡距离为2km ，用时为4min 故上坡速度115V =(km/min)，下坡速度22142V ==(km/min) 从学校返回家的过程中，原来的上下坡刚好颠倒过来，即上坡2km ，下坡1km 故上坡时间12t 15==10(min)，下坡时间21t 12==2(min) ∴总用时为：10+2=12(min)故选：B【点睛】本题考查从函数图象获取信息，解题关键是将函数图像中的数据与生活实际一一对应。

(易错题精选)初中数学有理数分类汇编附答案解析

（易错题精选）初中数学有理数分类汇编附答案解析一、选择题1．如图，数轴上每相邻两点距离表示1个单位，点A ，B 互为相反数，则点C 表示的数可能是（）A ．0B ．1C ．3D ．5 【答案】C【解析】【分析】根据相反数的几何意义：在数轴上，一组相反数所表示的点到原点的距离相等，即可确定原点的位置，进而得出点C 表示的数.【详解】∵点A ，B 互为相反数，∴AB 的中点就是这条数轴的原点，∵数轴上每相邻两点距离表示1个单位，且点C 在正半轴距原点3个单位长度， ∴点C 表示的数为3.故选C.【点睛】本题考查了相反数和数轴的知识.利用相反数的几何意义找出这条数轴的原点是解题的关键.2．如果实数a ，b 在数轴上的对应点的位置如图所示，那么下列结论正确的是（）A ．a b <B ．a b >-C ．2a >-D ．b a >【答案】D【解析】【分析】根据数轴可以发现a ＜b ，且-3＜a ＜-2，1＜b ＜2，由此即可判断以上选项正确与否．【详解】∵-3＜a ＜-2，1＜b ＜2，∴|a|＞|b|，∴答案A 错误；∵a ＜0＜b ，且|a|＞|b|，∴a+b ＜0，∴a ＜-b ，∴答案B 错误；∵-3＜a ＜-2，∴答案C 错误；∵a ＜0＜b ，∴b ＞a ，∴答案D 正确．故选：D ．【点睛】本题考查的是数轴与实数的大小比较等相关内容，会利用数轴比较实数的大小是解决问题的关键．3．实效m ，n 在数轴上的对应点如图所示，则下列各式子正确的是（）A ．m n >B ．n m ->C ．m n ->D ．m n <【答案】C【解析】【分析】从数轴上可以看出m 、n 都是负数，且m ＜n ，由此逐项分析得出结论即可．【详解】解：因为m 、n 都是负数，且m ＜n ，|m|＜|n|，A 、m ＞n 是错误的；B 、-n ＞|m|是错误的；C 、-m ＞|n|是正确的；D 、|m|＜|n|是错误的．故选：C ．【点睛】此题考查有理数的大小比较，关键是根据绝对值的意义等知识解答．4．下列说法错误的是（）A ．2 a 与()2a -相等B ()2a -2a -C ．3 a 3a -D ．a 与a -互为相反数【答案】D【解析】【分析】根据乘方、算术平方根、立方根、绝对值，以及相反数的定义，分别对每个选项进行判断，即可得到答案.【详解】解：A 、()2a -=2 a ，故A 正确；B ()22a a -=()2a -2a -B 正确；C 、3 a 3a -C 正确；D 、a a -=，故D 说法错误；故选：D.【点睛】本题考查了乘方、算术平方根、立方根、绝对值，以及相反数的定义，解题的关键是熟练掌握所学的定义进行解题.5．已知整数1a ，2a ，3a ，4a ⋯满足下列条件：10a =，21|1|a a =-+，32|2|a a =-+，43|3|a a =-+⋯依此类推，则2017a 的值为( )A ．1007-B ．1008-C ．1009-D ．2016- 【答案】B【解析】【分析】根据条件求出前几个数的值，再分n 是奇数时，结果等于12n --；n 是偶数时，结果等于2n -；然后把n 的值代入进行计算即可得解．【详解】解：10a =，21|1|011a a =-+=-+=-，32|2|121a a =-+=--+=-，43|3|132=-+=--+=-a a ，54|4|242=-+=--+=-a a ，……∴n 是奇数时，结果等于12n --；n 是偶数时，结果等于2n -； ∴20172017110082a -=-=-；故选：B ．【点睛】此题考查数字的变化规律，根据所求出的数，观察出n 为奇数与偶数时的结果的变化规律是解题的关键．6．如图是张小亮的答卷，他的得分应是（）A ．40分B ．60分C ．80分D ．100分【答案】A【解析】【分析】根据绝对值、倒数、相反数、立方以及平均数进行计算即可．【详解】解：①若ab=1，则a与b互为倒数，②（-1）3=-1，③-12=-1，④|-1|=-1，⑤若a+b=0，则a与b互为相反数，故选A．【点睛】本题考查了实数，掌握绝对值、倒数、相反数、立方根以及平均数的定义是解题的关键．7．在数轴上，点A，B在原点O的两侧，分别表示数a和3，将点A向左平移1个单位=，则a的值为（）．长度，得到点C．若OC OBA．3-B．2-C．1-D．2【答案】B【解析】【分析】先用含a的式子表示出点C,根据CO=BO列出方程,求解即可．【详解】解:由题意知:A点表示的数为a,B点表示的数为3, C点表示的数为a-1．因为CO=BO,所以|a-1| =3, 解得a=-2或4,∵a＜0,∴a=-2．故选B．【点睛】本题主要考查了数轴和绝对值方程的解法,用含a的式子表示出点C,是解决本题的关键．8．下面说法正确的是()A．1是最小的自然数；B．正分数、0、负分数统称分数C．绝对值最小的数是0；D．任何有理数都有倒数【答案】C【解析】【分析】0是最小的自然数，属于整数，没有倒数，在解题过程中，需要关注【详解】最小的自然是为0，A错误；0是整数，B错误；任何一个数的绝对值都是非负的，故绝对值最小为0，C正确；0无倒数，D错误【点睛】本题是有理数概念的考查，主要需要注意0的特殊存在9．2019-的倒数是（）A．2019 B．－2019 C．12019D．12019-【答案】C【解析】【分析】先利用绝对值的定义求出2019-，再利用倒数的定义即可得出结果.【详解】2019-=2019,2019的倒数为1 2019故选C【点睛】本题考查了绝对值和倒数的定义，熟练掌握相关知识点是解题关键.10．下列说法中不正确的是（）A．-3 表示的点到原点的距离是|-3|B．一个有理数的绝对值一定是正数C．一个有理数的绝对值一定不是负数D．互为相反数的两个数的绝对值一定相等【答案】B【解析】【分析】根据绝对值的意义以及相反数的意义逐项进行分析即可得答案.【详解】A、根据绝对值的意义|-3|表示在数轴上表示-3的点到原点的距离，故A选项正确，不符合题意；B、若这个有理数为0，则0的绝对值还是0，故B选项错误，符合题意；C、根据绝对值的意义，|a|的绝对值表示在数轴上表示a的点到原点的距离，故任意有理数的绝对值都为非负数，所以不可能为负数，故C选项正确，不符合题意；D、根据相反数的定义可知：只有符号不同的两数互为相反数，可知互为相反数的两数到原点的距离相等，即互为相反数的两个数的绝对值相等，故D选项正确，不符合题意，故选B．【点睛】本题考查了绝对值的意义，绝对值的代数意义为：正数的绝对值等于它本身；负数的绝对值等于它的相反数；0的绝对值还是0；绝对值的几何意义为：|a|表示在数轴上表示a 的这个点到原点的距离，熟练掌握绝对值的意义是解本题的关键．11．不论a 取什么值，下列代数式的值总是正数的是（）A ．1a +B ．1a +C ．2aD ．2(1)a + 【答案】B【解析】【分析】直接利用绝对值的性质以及偶次方的性质分别分析得出答案．【详解】A 、|a+1|≥0，故此选项错误；B 、|a|+1＞0，故此选项正确；C 、a 2≥0，故此选项错误；D 、（a+1）2≥0，故此选项错误；故选B ．【点睛】此题主要考查了偶次方的性质以及绝对值的性质，正确把握相关定义是解题关键．12．2019的倒数的相反数是（）A ．-2019B ．12019-C ．12019D ．2019 【答案】B【解析】【分析】先求2019的倒数，再求倒数的相反数即可.【详解】2019的倒数是12019， 12019的相反数为12019-，所以2019的倒数的相反数是12019-，故选B ．【点睛】本题考查了倒数和相反数，熟练掌握倒数和相反数的求法是解题的关键．13．数轴上A ，B ，C 三点所表示的数分别是a ，b ，c ，且满足||||||c b a b a c ---=-，则A ，B ，C 三点的位置可能是（）A ．B ．C ．D ．【答案】C【解析】【分析】由A 、B 、C 在数轴上的位置判断出a 、b 、c 的大小关系，根据绝对值性质去绝对值符号，判断左右两边是否相等即可.【详解】当a c b ＜＜时，||||c b a b b c a b a c ---=-+-=-，180°-66?38=113?22′′，此选项错误；B 、当a ＜b ＜c 时，||||2c b a b c b a b c a b ---=-+-=+-，44A-mB=，此项错误；C 、当c ＜a ＜b 时，||||c b a b b c a b a c ---=-+-=-，||a c a c -=-，此项正确D 、当c ＜b ＜a 时，||||2c b a b b c a b c a b ---=--+=--+，||a c a c -=-，此选项错误；故选C.【点睛】本题主要考查绝对值性质:正数绝对值等于本身，0的绝对值是0，负数绝对值等于其相反数.14．若320,a b -+=则+a b 的值是（）A ．2B 、1C 、0D 、1-【答案】B【解析】试题分析：由题意得，3﹣a=0，2+b=0，解得，a=3，b=﹣2，a+b=1，故选B ．考点：1．非负数的性质：算术平方根；2．非负数的性质：绝对值．15．实数a,b,c 在数轴上的对应点的位置如图所示，则正确的结论是（）A ．a b >B ．0a b +>C ．0ac >D ．a c > 【答案】D【解析】【分析】根据数轴的特点：判断a 、b 、c 正负性，然后比较大小即可．【详解】根据数轴的性质可知：a ＜b ＜0＜c ，且|c|＜|b|＜|a|；所以a ＞b ，0a b +>，ac ＞0错误；|a|＞|c|正确；故选D ．【点睛】本题考查实数与数轴的关系，关键是根据实数在数轴上的位置判断字母的正负性，根据实数在数轴上离原点的距离判断绝对值的大小．16．实数,a b 在数轴上对应的点位置如图所示，则化简22||a a b b +++的结果是（）A ．2a -B ．2b -C ．2a b +D ．2a b -【答案】A【解析】【分析】2,a a = 再根据去绝对值的法则去掉绝对值，合并同类项即可．【详解】解：0,,a b a b Q ＜＜＞ 0,a b ∴+＜22||a a b b a a b b ∴++=+++()a a b b =--++a ab b =---+2.a =-故选A ．【点睛】本题考查的是二次根式与绝对值的化简运算，掌握化简的法则是解题关键．17．已知点P 的坐标为（a ，b ）（a ＞0），点Q 的坐标为（c ，3），且|a ﹣c|+7b-=0，将线段PQ向右平移a个单位长度，其扫过的面积为20，那么a+b+c的值为（）A．12 B．15 C．17 D．20【答案】C【解析】【分析】由非负数的性质得到a=c，b=7，P（a，7），故有PQ∥y轴，PQ=7-3=4，由于其扫过的图形是矩形可求得a，代入即可求得结论．【详解】b-=0，∵且|a-c|++7∴a=c，b=7，∴P（a，7），PQ∥y轴，∴PQ=7-3=4，∴将线段PQ向右平移a个单位长度，其扫过的图形是边长为a和4的矩形，∴4a=20，∴a=5，∴c=5，∴a+b+c=5+7+5=17，故选C.【点睛】本题主要考查了非负数的性质，坐标的平移，矩形的性质，能根据点的坐标判断出PQ∥y 轴，进而求得PQ是解题的关键．18．如图，将一刻度尺放在数轴上（数轴的单位长度是1cm），刻度尺上的“0cm”和“6cm”分别对应数轴上表示﹣2和实数x的两点，那么x的值为（）A．3 B．4 C．5 D．6【答案】B【解析】【分析】根据数轴的定义进行分析即可.【详解】∵由图可知，﹣2到x之间的距离为6，∴x表示的数为：﹣2+6＝4，故选：B．【点睛】本题考查了用数轴表示实数，题目较为简单，解题的关键是根据如何根据一个已知点和两点的距离求另一个点．19．若实数a ，b ，c ，d 在数轴上的对应点的位置如图所示，则正确的结论是( )A ．a <-5B ．b +d <0C ．||||a c <D ．c d <【答案】D【解析】【分析】根据数轴得到-5<a<b<0<c<d ，且a d b c >>>，再依次判断各选项即可得到答案.【详解】由数轴得-5<a<b<0<c<d ，且a d b c >>>，∴A 错误；∵b+d>0，故B 错误； ∵a c >，∴C 错误； ∵d c >，c>0， ∴c d <D 正确，故选：D.【点睛】此题考查数轴上数的大小关系，绝对值的性质，有理数的加法法则.20．下列语句正确的是（）A ．近似数0．010精确到百分位B ．｜x-y ｜=｜y-x ｜C ．如果两个角互补，那么一个是锐角，一个是钝角D ．若线段AP=BP ，则P 一定是AB 中点【答案】B【解析】【分析】A 中,近似数精确位数是看小数点后最后一位;B 中,相反数的绝对值相等;C 中,互补性质的考查;D 中,点P 若不在直线AB 上则不成立【详解】A 中,小数点最后一位是千分位,故精确到千分位,错误;B 中,x －y 与y －x 互为相反数,相反数的绝对值相等,正确；C 中，若两个角都是直角，也互补，错误；D 中，若点P 不在AB 这条直线上，则不成立，错误故选：B【点睛】概念的考查，此类题型，若能够举出反例来，则这个选项是错误的。

(易错题精选)初中数学命题与证明的真题汇编附答案

（易错题精选）初中数学命题与证明的真题汇编附答案一、选择题1．下列命题的逆命题成立的是（）A．对顶角相等B．全等三角形的对应角相等C．如果两个数相等，那么它们的绝对值相等D．两直线平行，同位角相等【答案】D【解析】【分析】写出各个命题的逆命题，然后判断是否成立即可．【详解】解：A、逆命题为相等的角为对顶角，不成立；B、逆命题为对应角相等的三角形全等，不成立；C、逆命题为绝对值相等的两个数相等，不成立；D、逆命题为同位角相等，两直线平行，成立，故选：D．【点睛】本题考查了命题与定理的知识，解题的关键是能够正确的写出各个命题的逆命题，难度不大．2．下列定理中，逆命题是假命题的是（）A．在一个三角形中，等角对等边B．全等三角形对应角相等C．有一个角是60度的等腰三角形是等边三角形D．等腰三角形两个底角相等【答案】B【解析】【分析】先把一个命题的条件和结论互换就得到它的逆命题，再进行判断即可．【详解】解：A、逆命题为：在一个三角形中等边对等角，逆命题正确，是真命题；B、逆命题为：对应角相等的三角形是全等三角形，逆命题错误，是假命题；C、逆命题为：如果一个三角形是等边三角形，那么它是一个等腰三角形而且有一个内角等于60°，逆命题正确，是真命题；D、逆命题为：两个角相等的三角形是等腰三角形，逆命题正确，是真命题；故选：B．【点睛】本题考查了命题与定理的知识，解题的关键是能够正确的写出原命题的逆命题．3．下列命题中①等腰三角形底边的中点到两腰的距离相等②如果两个三角形全等，则它们必是关于直线成轴对称的图形③如果两个三角形关于某直线成轴对称，那么它们是全等三角形④等腰三角形是关于底边中线成轴对称的图形⑤一条线段是关于经过该线段中点的直线成轴对称的图形正确命题的个数是（）A ．2个B ．3个C ．4个D ．5个【答案】A【解析】【分析】根据等腰三角形的性质、轴对称图形的定义、全等三角形的判定逐个判断即可．【详解】根据等腰三角形的三线合一可知，底边中点在顶角角平分线上，再根据角平分线的性质可知，其到两腰的距离相等，则命题①正确全等的三角形不一定是成轴对称，则命题②错误成轴对称的两个三角形一定全等，则命题③正确等腰三角形是以底边中线所在直线为对称轴的轴对称图形，则命题④错误成轴对称的图形必须是两个，一个图形只能是轴对称图形，则命题⑤错误综上，正确命题的个数是2个故选：A ．【点睛】本题考查了等腰三角形的性质、轴对称图形的定义、全等三角形的判定等知识点，掌握理解各定义与性质是解题关键．4．已知：ABC ∆中，AB AC =，求证：90O B ∠<，下面写出可运用反证法证明这个命题的四个步骤：①∴180O A B C ∠+∠+∠>，这与三角形内角和为180O 矛盾,②因此假设不成立．∴90O B ∠<,③假设在ABC ∆中，90O B ∠≥,④由AB AC =，得90O B C ∠=∠≥，即180O B C ∠+∠≥．这四个步骤正确的顺序应是（）A ．③④②①B ．③④①②C ．①②③④D ．④③①②【答案】B【解析】【分析】根据反证法的证明步骤“假设、合情推理、导出矛盾、结论”进行分析判断即可.【详解】题目中“已知：△ABC 中，AB=AC ，求证：∠B ＜90°”，用反证法证明这个命题过程中的四个推理步骤：应该为：(1)假设∠B ≥90°，(2)那么，由AB=AC，得∠B=∠C≥90°，即∠B+∠C≥180°，(3)所以∠A+∠B+∠C＞180°，这与三角形内角和定理相矛盾，(4)因此假设不成立．∴∠B＜90°，原题正确顺序为：③④①②，故选B．【点睛】本题考查反证法的证明步骤，弄清反证法的证明环节是解题的关键.5．下列结论中，不正确的是（）A．两点确定一条直线B．两点之间，直线最短C．等角的余角相等D．等角的补角相等【答案】B【解析】【分析】根据直线线段的性质和余角、补角的定义逐项分析可得出正确选项．【详解】A．两点确定一条直线，正确；B．两点之间，线段最短，所以B选项错误；C．等角的余角相等，正确；D．等角的补角相等，正确．故选B考点：定理6．下列命题的逆命题不成立的是（）A．两直线平行，同旁内角互补B．如果两个实数相等，那么它们的平方相等C．平行四边形的对角线互相平分D．全等三角形的对应边相等【答案】B【解析】【分析】把一个命题的条件和结论互换就得到它的逆命题．分析是否为真命题，需要分别分析各题设是否能推出结论，从而利用排除法得出答案．【详解】选项A，两直线平行，同旁内角互补的逆命题是同旁内角互补，两直线平行，正确，成立；选项B，如果两个实数相等，那么它们的平方相等的逆命题是平方相等的两个数相等，错误，不成立，如（﹣3）2＝32，但﹣3≠3；选项C，平行四边形的对角线互相平分的逆命题是对角线互相平分的四边形是平行四边形，正确，成立；选项D，全等三角形的对应边相等的逆命题是对应边相等的三角形全等，正确，成立；故选B．【点睛】本题考查了互逆命题的知识，两个命题中，如果第一个命题的条件是第二个命题的结论，而第一个命题的结论又是第二个命题的条件，那么这两个命题叫做互逆命题．其中一个命题称为另一个命题的逆命题．7．下列说法中，正确．．的是( )A．图形的平移是指把图形沿水平方向移动.B．平移前后图形的形状和大小都没有发生改变.C．“相等的角是对顶角”是一个真命题D．“直角都相等”是一个假命题【答案】B【解析】图形的平移是指在平面内，将一个图形上的所有点都按照某个方向作相同距离的移动，这样的图形运动叫做图形的平移运动，简称平移，平移前后图形的形状和大小都没有发生改变．而相等的角不一定是对顶角，C是一个假命题，直角都相等是真命题．故选B8．下列命题：①两条直线被第三条直线所截，同位角相等；②两点之间，线段最短；③相等的角是对顶角；④直角三角形的两个锐角互余；⑤同角或等角的补角相等．其中真命题的个数是（）A．2个B．3个C．4个D．5个【答案】B【解析】【分析】【详解】解：命题①两条平行线被第三条直线所截，同位角相等，错误，为假命题；命题②两点之间，线段最短，正确，为真命题；命题③相等的角是对顶角，错误，为假命题；命题④直角三角形的两个锐角互余，正确，为真命题；命题⑤同角或等角的补角相等，正确，为真命题，故答案选B．考点：命题与定理．9．下列命题是真命题的是（）A．中位数就是一组数据中最中间的一个数B．一组数据的众数可以不唯一C．一组数据的标准差就是这组数据的方差的平方根D．已知a、b、c是Rt△ABC的三条边，则a2+b2＝c2【答案】B【解析】【分析】正确的命题是真命题，根据定义判断即可.【详解】解：A、中位数就是一组数据中最中间的一个数或着是中间两个数的平均数，故错误；B、一组数据的众数可以不唯一，故正确；C、一组数据的标准差是这组数据的方差的算术平方根，故此选项错误；D、已知a、b、c是Rt△ABC的三条边，当∠C＝90°时，则a2+b2＝c2，故此选项错误；故选：B．【点睛】此题考查真命题的定义，掌握定义，准确理解各事件的正确与否是解题的关键.10．以下说法中：（1）多边形的外角和是360 ；（2）两条直线被第三条直线所截，内错角相等；（3）三角形的3个内角中，至少有2个角是锐角.其中真命题的个数为（）A．0 B．1 C．2 D．3【答案】C【解析】【分析】利用多边形的外角和定理、平行线的性质及三角形的内角和定理分别判断后即可确定正确的选项．【详解】解：（1）多边形的外角和是360°，正确，是真命题；（2）两条平行线被第三条直线所截，内错角相等，故错误，是假命题；（3）三角形的3个内角中，至少有2个角是锐角，正确，是真命题，真命题有2个，故选：C．【点睛】考查了命题与定理的知识，解题的关键是了解多边形的外角和定理、平行线的性质及三角形的内角和定理，难度不大．11．下列命题的逆命题成立的有( )①勾股数是三个正整数 ②全等三角形的三条对应边分别相等③如果两个实数相等，那么它们的平方相等 ④平行四边形的两组对角分别相等 A ．1个B ．2个C ．3个D ．4个【答案】B【解析】【分析】先写出每个命题的逆命题，再分别根据勾股数的定义、三角形全等的判定、平方根的定义、平行四边形的判定逐个判断即可．【详解】①逆命题：如果三个数是正整数，那么它们是勾股数反例：正整数1,2,3，但222123+?，即它们不是勾股数，则此逆命题不成立 ②逆命题：三条对应边分别相等的两个三角形全等由SSS 定理可知，此逆命题成立③逆命题：如果两个实数的平方相等，那么这两个实数相等反例：222(2)4=-=，但22≠-，则此逆命题不成立④逆命题：两组对角分别相等的四边形是平行四边形由平行四边形的判定可知，此逆命题成立综上，逆命题成立的有2个故选：B ．【点睛】本题考查了命题的相关概念、勾股数的定义、三角形全等的判定、平方根的定义、平行四边形的判定，正确写出各命题的逆命题是解题关键．12．下列命题中，是真命题的是（）A ．将函数y ＝12x +1向右平移2个单位后所得函数的解析式为y ＝12x B ．若一个数的平方根等于其本身，则这个数是0和1 C ．对函数y ＝2x，其函数值y 随自变量x 的增大而增大 D ．直线y ＝3x +1与直线y ＝﹣3x +2一定互相平行【答案】A【解析】【分析】利用一次函数的性质、平方根的定义、反比例函数的性质等知识分别判断后即可确定正确的选项．【详解】解：A 、将函数y ＝12x +1向右平移2个单位后所得函数的解析式为y ＝12x ，正确，符合题意； B 、若一个数的平方根等于其本身，则这个数是0，故错误，是假命题，不符合题意；C 、对函数y ＝2x，其函数值在每个象限内y 随自变量x 的增大而增大，故错误，是假命题，不符合题意； D 、直线y ＝3x +1与直线y ＝﹣3x +2因比例系数不相等，故一定不互相平行，故错误，是假命题，故选：A ．【点睛】本题考查了判断命题真假的问题，掌握一次函数的性质、平方根的定义、反比例函数的性质等知识是解题的关键．13．下列命题是真命题的是（）A ．方程23240x x --=的二次项系数为3，一次项系数为-2B ．四个角都是直角的两个四边形一定相似C ．某种彩票中奖的概率是1%，买100张该种彩票一定会中奖D ．对角线相等的四边形是矩形【答案】A【解析】【分析】根据所学的公理以及定理，一元二次方程的定义，概率等知识，对各小题进行分析判断，然后再计算真命题的个数．【详解】A 、正确．B 、错误，对应边不一定成比例．C 、错误，不一定中奖．D 、错误，对角线相等的四边形不一定是矩形.故选：A ．【点睛】此题考查命题与定理，熟练掌握基础知识是解题关键．14．用三个不等式a ＞b ，ab ＞0，1a ＞1b中的两个不等式作为题设，余下的一个不等式作为结论组成一个命题，组成真命题的个数为（） A ．0B ．1C ．2D ．3 【答案】A【解析】【分析】由题意得出3个命题，由不等式的性质再判断真假即可．【详解】解：①若a＞b，ab＞0，则1a＞1b；假命题：理由：∵a＞b，ab＞0，∴a＞b＞0，∴1a＜1b；②若ab＞0，1a＞1b，则a＞b，假命题；理由：∵ab＞0，∴a、b同号，∵1a＞1b，∴a＜b；③若a＞b，1a＞1b，则ab＞0，假命题；理由：∵a＞b，1a＞1b，∴a、b异号，∴ab＜0．∴组成真命题的个数为0个；故选：A．【点睛】本题考查了命题与定理、不等式的性质、命题的组成、真命题和假命题的定义；熟练掌握命题的组成和不等式的性质是解题的关键．15．下列命题中，其中真命题的个数是（）①平面直角坐标系内的点与实数对一一对应；②内错角相等；③平行于同一条直线的两条直线互相平行；④对顶角相等A．1个B．2个C．3个D．4个【答案】B【解析】【分析】正确的命题是真命题，根据真命题的定义依次进行判断.【详解】①平面直角坐标系内的点与有序实数对一一对应，是假命题；②两直线平行，内错角相等，是假命题；③平行于同一条直线的两条直线不一定相互平行，是真命题；④对顶角相等，是真命题；故选：B．【点睛】此题考查真命题的定义，正确掌握坐标与图形，平行线的性质，平行公理，对顶角性质是解题的关键.16．下列说法正确的是()A．若a＞b，则a2＞b2B．若三条线段的长a、b、c满足a+b＞c，则以a、b、c为边一定能组成三角形C．两直线平行，同旁内角相等D．三角形的外角和为360°【答案】D【解析】【分析】利用特例对A进行分析，利用三角形三边关系、平行线的性质、三角形外角的性质分别对B、C、D进行分析判断．【详解】A、若a＞b，则不一定有a2＞b2，比如a＝0,b＝﹣1，故本选项错误；B、若三条线段的长a、b、c满足a+b＞c，则以a、b、c为边不一定能组成三角形，故本选项错误；C、两直线平行，同旁内角互补，故本选项错误；D、三角形的外角和为360°，故本选项正确；故选：D【点睛】本题考查真假命题的判断，解题的关键是根据相关知识对命题进行分析判断．17．39．下列命题中，是假命题的是（）A．同旁内角互补B．对顶角相等C．直角的补角仍然是直角D．两点之间，线段最短【答案】A【解析】同旁内角不一定互补，同旁内角互补的条件是两直线平行，故选A.18．下列命题的逆命题不正确的是（）A．全等三角形的对应边相等B．两直线平行，同位角相等C ．等腰三角形的两个底角相等D ．矩形的对角线相等．【答案】D【解析】【分析】根据求逆命题的原则，把原命题的结论作为条件，原命题的条件作为结论得到的命题是原命题的逆命题，逐一判断逆命题的正误即可．【详解】解：A 的逆命题是：对应边相等的三角形是全等三角形，正确；B 的逆命题是：同位角相等，两直线平行，正确；C 的逆命题是：两底角相等的三角形是等腰三角形，正确；D 的逆命题是：对角线相等的四边形是矩形，错误故选：D【点睛】本题考查逆命题、全等三角形的判定、平行线的判定、等腰三角形的判定、矩形的判定，解题的关键是正确找出各选项的逆命题．19．能说明命题“关于x 的方程240x x m -+=一定有实数根”是假命题的反例为（） A ．1m =-B ．0m =C ．4m =D ．5m =【答案】D【解析】【分析】利用m=5使方程x 2-4x+m=0没有实数解，从而可把m=5作为说明命题“关于x 的方程x 2-4x+m=0一定有实数根”是假命题的反例．【详解】当m=5时，方程变形为x 2-4x+m=5=0，因为△=（-4）2-4×5＜0，所以方程没有实数解，所以m=5可作为说明命题“关于x 的方程x 2-4x+m=0一定有实数根”是假命题的反例．故选D ．【点睛】本题考查了命题与定理：命题的“真”“假”是就命题的内容而言．任何一个命题非真即假．要说明一个命题的正确性，一般需要推理、论证，而判断一个命题是假命题，只需举出一个反例即可．20．用反证法证明“三角形的三个外角中至多有一个锐角”，应先假设( )A ．三角形的三个外角都是锐角B ．三角形的三个外角中至少有两个锐角C ．三角形的三个外角中没有锐角D ．三角形的三个外角中至少有一个锐角【答案】B【解析】【分析】反证法的步骤中，第一步是假设结论不成立，反面成立．【详解】解：用反证法证明“三角形的三个外角中至多有一个锐角”，应先假设三角形的三个外角中至少有两个锐角，故选B．【点睛】.在假设结论不成立时要注意考虑结考查了反证法，解此题关键要懂得反证法的意义及步骤论的反面所有可能的情况，如果只有一种，那么否定一种就可以了，如果有多种情况，则必须一一否定．。

初中英语易错题 (含答案解析)

初中英语易错题（附答案解析）（100分）1、There is __ water. 【单选题】（5.0分）A.noB.not正确答案: A答案解析: no water表示“没有水”；not water 表示“不是水”。

2、He is ___. 【单选题】（5.0分）A.tallB.high正确答案: A答案解析: high指海拔高，形容身高一般适用tall。

3、He walks ____. 【单选题】（5.0分）A.fastB.fastly正确答案: A答案解析: fast可以直接作为副词，含义为“快地”。

4、I used to think ___ of you. 【单选题】（5.0分）A.highB.highly正确答案: B答案解析: think highly of sth./sb.可用过固定短语，意为“高度欣赏...,highly可形容抽象的高。

5、He ___ Beijing yesterday, now he is in Shanghai. 【单选题】（5.0分）A.leftB.left for正确答案: A答案解析: leave(left的原型) 视sp.表示离开某地，leave for sp.表示离开去往某地，for表目的。

6、Dont you understand? He __ you! 【单选题】（5.0分）A.cares aboutB.cares for正确答案: B答案解析: care for 可指”喜欢“，而care about大多指”在意，关心“。

7、The girl needs some ___. 【单选题】（5.0分）A.clothB.clothesC.clothing正确答案: B答案解析: clothes统指各种衣服，谓语动词永远是复数。

clothing指”服装“。

8、The annoying ____ keeps me awake. 【单选题】（5.0分）A.soundB.noiseC.voice正确答案: B答案解析: sound自然界各种各样的声音voice指人的嗓音noise特指惹人烦的噪音9、The police is investigating(调查) the true ___ of the accident. 【单选题】（5.0分）A.causeB.reason正确答案: A答案解析: cause偏指“造成不好结果的原因/诱因”；reason偏中性，指”普通的原因“。

历年高考英语单选题易错题汇编(ready)

历年高考英语易错题难题好题汇编及解析1、Stop making so much noise ____ the neighbor will start complaining.A、or elseB、but stillC、and thenD、so that2、We hope to go to the beach tomorrow, but we won’t go ____ it’s raining.A、ifB、whenC、thoughD、because3、——The weather is too cold ____ March this year.——It was still ____ when I came here years ago.A、for; colderB、in; coldC、in; hotD、for; hotter4、——How much vinegar did you put in the soup?——I’m sorry to say, ____. I forget.A、noB、no oneC、nothingD、none5、He is only too ready to help others, seldom, ____, refusing them when they turn to him.A、if neverB、if everC、if notD、if any6、——What should I wear to attend his wedding party?——Dress ____ you like.A、whatB、howeverC、whateverD、how7、——The research on the new bird flu virus vaccine is challenging and demanding. Who do you think can do the job?——____ my students have a try?A、ShallB、MustC、WillD、May8、I’d like to live somewhere ____ the sun shines all year long.A、whichB、thatC、whereD、in which9、I ____ to go for a walk, but someo ne called and I couldn’t get away.A、was planningB、plannedC、had plannedD、would plan10、——Your book, Tommy?——No, Mom, it’s my friend’s.——Remember to return it to ____ name is on it.A、whatB、whichC、whoseD、whosever11、Thank you for sending us ____ fresh vegetables of many kinds. You have done us ____ a great service.A、不填；aB、the；aC、不填；不填D、the；不填12、Now that we ____ all the money, it’s no use turning on me and saying it’s all my fault.A、had lostB、lostC、have lostD、lose13、We had a really bad time about six months ago but now things are ____.A、looking upB、coming upC、making upD、turning up14、——When did it begin to snow?——It started ____ the night.A、duringB、byC、fromD、at15、Young as he is, David has gained ____ rich experience in ____ society.A、the; theB、a; 不填C、不填；不填D、不填；the16、____ from endless homework on weekends, the students now find their own activities, such as taking a ride together to watch the sunrise.A、FreedB、FreeingC、To freeD、having freed17、——So you missed the meeting.——____. I got there five minutes before it finished.A、Not at allB、Not exactlyC、Not especiallyD、Not really18、——Do you mind if I smoke?——____A、Why not?B、Yes, help yourselfC、Go aheadD、Yes, but you’d better not19、——We must thank you for taking the trouble to cook us a meal.——____.A、With pleasureB、It doesn’t matterC、It was no trouble at allD、By all means20、____ the temperature might drop, coal was prepared for warming.A、To considerB、ConsideredC、ConsideringD、To be considered21、——Tom, you are caught late again.——Oh, ____.A、not at allB、just my luckC、never mindD、that’s all right22、——What do you think of the concert?——I reall y enjoy it. I didn’t expect it was ____ wonderful.A、asB、moreC、mostD、very23、The engineers made two big plans for the dam, ____ was never put in force.A、one of themB、whichC、one of whichD、every one of which24、I have no one ____ me, for I am a new comer here.A、helpB、helpingC、to helpD、to have helped25、The little girl couldn’t work the problem out. She wasn’t ____ clever.A、thatB、muchC、enoughD、too26、Listen! His family must be quarrelling, ____?A、mustn’t itB、isn’t itC、aren’t theyD、needn’t they27、The police have ____ power to deal with such matters by ____ law.A、the; theB、不填；不填C、不填；theD、the；不填28、Jack felt unhappy as they all went outing ____ him.A、exceptB、butC、withoutD、besides29、That she hadn’t kept her ____ on her work resulted in the failure.A、headB、heartC、brainD、mind30、——Did your sister pass the exam?——She failed and is in low spirits.——I’m sorry for her.——____.A、Thank youB、You’re welcomeC、I would think soD、Never mind31、The students spent as much time getting trained as they ____ studying.A、dislikedB、wereC、hadD、did32、It was believed that things would get worse, but ____ it is they are getting better.A、beforeB、afterC、becauseD、as33、As time went by, the plan stuck ____ fairly practical.A、to provedB、to provingC、provedD、to be proved34、More than one ____ the people heart and soul.A、official has servedB、officials have servedC、official has served forD、officials have served for35、The president stood by a window inside the room, ____, looking over the square.A、where I enteredB、into which I enteredC、which I enteredD、that I entered36、Though I ____ to go abroad, I changed my mind and decided to stay with my family.A、had wantedB、wantedC、would wantD、did want37、My brother is very tall. The little bed won’t ____ for him.A、prepareB、matchC、fitD、do38、——Thank you so much for the lovely evening, Dennis.——Y ou’re quite welcome, Julie. ____. We’d been looking forward to seeing you.A、Were glad to meet youB、I’m afraid you didn’t have a good timeC、Thank you for your comingD、Just stay a little longer, please39、Scientists say they have found a way to produce the human body’s own cancer-killing cells through gene treatment, ____ new hope to cancer sufferers.A、offeringB、showingC、takingD、making40、We are going to discuss the way of reading works ____ it is used for real life purposes,and this should give you a better understanding of it.A、thatB、whichC、whereD、when41、——The dinner was delicious!——I agree. I am so full.——That’s too bad. But some dessert ____.A、has orderedB、will be orderedC、has been orderedD、was going to be ordered42、——This wall of air is an effective answer to the problem and it ____ work.——But it is a question to put such a wall of air around the statue.A、mayB、mustC、shouldD、could43、We should know that we can only reach the top if we are ready to ____ and learn from failure.A、deal withB、depend onC、carry onD、go with44、——Good evening. I ____ to see Miss Jessic.——Oh! Good evening. I’m sorry, but she is not in.A、cameB、comeC、have comeD、had come45、——Please call me at 8:00 tomorrow morning. I’m kind of forgetful.——Don’t worry about that, you’ll be surely ____.A、remindedB、toldC、warnedD、informed46、——What’s the matt er with Tim?——Oh, Tim’s cellphone was left in a taxi accidentally, never ____ again.A、to findB、to be foundC、findingD、being found47、A terrible earthquake happened in that district at the end of 2004, ____ many countries inthe world paid close attention to this.A、whereB、whenC、whichD、what48、——How come a simple meal like this costs so much?——We have ____ in your bill the cost of the cup you broke just now.A、addedB、includedC、containedD、charged49、——You didn’t wait for Mr. Black last night, did you?——No, but we ____. He didn’t return home at all.A、couldn’t haveB、needn’t haveC、didn’t need toD、should wait have50、——How do you think I should receive the reporter?——____ you feel about him, try to be polite.A、HowB、WhatC、WhateverD、However51、____ has recently been done to provide more buses for the people, a shortage of public vehicles remains a serious problem.A、ThatB、WhatC、In spite of whatD、Though what52、As we have much time left, let’s discuss the matter ____ tea and cake.A、overB、withC、byD、at53、Mr Black must be worried about something. You can ____ it from the look on his face.A、reasonB、recognizeC、readD、realize54、——Can I pay the bill by check?——Sorry, sir. But it is the management rule of our hotel that payment ____ be made in cash.A、shallB、needC、willD、can55、If you win the competition, you will be given ____ to Europe for two.A、a free 7-day tripB、a free trip for 7-dayC、a 7-day free tripD、a trip for 7-day free56、——Hey, Kelin. Happy new year! ____?——Ok, I guess. My grandma kept cooking and cooking, so I just kept eating.A、How was your breakB、How is your grandmaC、Where did you go for holidayD、What did you do in your holiday57、——Would you mind giving your advice on how to improve our business management?——if you make ____ most of the equipment, there will be ____ rise in production.A、不填；不填B、the；aC、不填；aD、the；不填58、——Will $200 ____ the cost of the damage?——I’m afraid not. I need at least $100 more.A、doB、includeC、coverD、afford59、If you live in the country or have ever visited there, ____ are that you have heard birds singing to welcome the new day.A、situationsB、factsC、dancesD、possibilities60、I ____ you, but I didn’t think you would listen to me.A、could have toldB、must have toldC、should tellD、might tell61、This problem may lead to more serious ones if ____ unsolved.A、makingB、remainedC、keepingD、left62、I have no dreams ____ to have a happy life.A、rather thanB、more thanC、other thanD、less than63、——You know Mr. Green has been ill for days?——Yes, I wonder if he is ____ better now.A、someB、muchC、anyD、no64、$100 a month could hardly ____ the cost of his life in such a big city in this country.A、spendB、takeC、coverD、meet65、Working in the kitchen for years made Tom ____ a good cook.A、forB、intoC、ofD、as66、She was such a proud person that she would die ____ she would admit she was wrong.A、rather thanB、untilC、afterD、before67、——Are you through with your homework?——Well, ____.A、sort ofB、go aheadC、why notD、that’s OK68、——What field will your son go into after graduation from Nanjing University?——I’m not quite certain, but he ____ a good teacher of English.A、promisesB、becomesC、makesD、proves69、My mother is always warning me when I go out, “Don’t get off the bus ____ it is stopping.”A、untilB、beforeC、whileD、after70、The dance performed by the disabled actors is really a hit, but years ago no one ____ they were to achieve such great success.A、must have imaginedB、could have imaginedC、should have imaginedD、would have imagined71、The young lady prefers dressing up for a party to ____ by others.A、be noticedB、being noticedC、having been noticedD、have been noticed72、Before the war broke out, many people ____ possessions they could not take with them.A、threw awayB、put awayC、gave awayD、carried away73、____ the pressure from work, teachers have to deal with psychological problems caused by interpersonal relationship.A、As far asB、As long asC、As well asD、As soon as74、——I hear your aunt likes travel, music, clothes and fine food.——Oh, yeah, and music may have been ____ of her tastes.A、the rather more respectableB、much the most respectableC、very the most respectableD、even more respectable one75、____ children tend to prefer sweets to meat.A、The mostB、MostC、Most ofD、The most of the76、——He looks very hot and dry.——So ____ if you had a temperature of 103.A、would youB、will youC、would you have beenD、do you77、In 1927 Benjamin Franklin founded one of the first adult-education organizations, ____ the Junto.A、has been calledB、to callC、a group calledD、which group called78、The car ____ at the present speed until it reaches the foot of the mountain at about nineo’c lock tonight.A、wentB、is goingC、goesD、will be going79、——You didn’t invite Mary to the ball?——____ her, too?A、Must I inviteB、Should I have invitedC、Must I have invitedD、Should I invite80、The number 9.11 is a special number, ____, I think, that will be remembered by the Americans forever.A、whatB、itC、whichD、one81、Will you see to ____ that my birds are looked after well while I’m away?A、themB、yourselfC、itD、me82、Many teens don’t get enough sleep because they have too much homework, which ____ them up at night.A、makesB、breaksC、turnsD、keeps83、——Ms Lin looks rather a kind lady.——But in fact she is cold and hard on us. You ____ believe it!A、shouldn’tB、wouldn’tC、mustn’tD、needn’t84、The program is like a window on the world ____ you sit by it and fix your attention on whatit shows.A、ifB、asC、whileD、unless85、____ the search engine just gave me some brief introductions rather than the whole contentof the book to read.A、LuckilyB、MostlyC、FunnilyD、Disappointingly86、——Did you know any French before you arrived in Washington?——Never ____ it, actually.A、had I learnedB、have I learnedC、I learnedD、was I learning87、In fact, more and more people ____ to live a greener, healthier and more environmentally “green life”.A、choseB、chooseC、are choosingD、have chosen88、A special dinner there might include Chinese pork dish, British roast beef and French-style vegetables. Boiled rice ____ just about everything.A、is served withB、will serveC、serves withD、is served89、The professor walked onto the platform and seated himself in a chair, ____ for answering questions.A、had preparedB、being preparedC、preparingD、prepared90、In Scandinavian countries it is common ____ for the husband to stay at home to look afterthe baby.A、useB、senseC、practiceD、idea91、——Why was our foreign teacher unhappy yesterday?——News about the tsunami striking her country ____ an attack of homesickness.A、set forB、set outC、set aboutD、set off92、——We are informed that the Weifang International Kite Festival starts at 7:00.——Oh, I didn’t expect it was so early! I ____ to go out for dinner with my friends first.A、was planningB、am planningC、have been planningD、have planned93、____ abroad for a tour can be a great honor for an ordinary person like me.A、TakenB、TakingC、Being takenD、Having been taken94、——Did your classmate accept your invitation?——No, he ____ refused.A、as far asB、as well asC、as soon asD、as good as95、I spent the whole day repairing the motorbike. The work was ____ simple.A、nothing butB、anything butC、something ofD、all except96、——Not getting that job was a big let-down.——Don’t worry. Something better will ____.A、come alongB、take onC、go byD、fall behind97、____ the help of experienced career instructors, this type of job-hunting training ____ tobe very efficient.A、By; has provedB、With; has provedC、Under; is provingD、With; is proved98、To get as much firsthand information as possible, inspectors will hold workshops and distribute questionnaires, ____?A、isn’t itB、won’t itC、aren’t theyD、won’t they99、It’s a bad practice to ____ children much money as a New Year gift.A、promiseB、permitC、admitD、allow100、By the time you arrive home, I ____, so please don’t make any noise when you come in.A、shall have been sleepingB、shall have sleptC、shall sleepD、shall be sleeping 101、Doing your homework is a sure way to improve your test scores, and this is especially true ____ it comes to classroom tests.A、beforeB、sinceC、whenD、after102、If you don’t keep the meat in the refrigerator on such a hot day, it may ____.A、go outB、go awayC、go offD、go down 103、His letter was especially welcome as I ____ from him for long.A、haven’t heardB、would not heardC、hadn’t heardD、didn’t heard 104、Examination compositions, together with most business letters and government reports, are the main situations ____ formal language is used.A、in whichB、on whichC、of whichD、for which 105、There aren’t many seats left for the concert; you had better make sure ____ two today.A、gettingB、to have gotC、that you getD、that you will get 106、——You can’t imagine ____ fantastic fun web chatting is.——Really? But it may cause a lot of trouble sometimes.A、whatB、howC、whyD、so107、____ friend of my grandfather’s will come tomorrow. I’m wondering how old ____ man he might be.A、The; aB、The; theC、A; aD、A; the 108、——Who is making so much noise in the garden?——____ the children.A、There areB、They areC、That isD、It is 109、The Cleveland Cavaliers ____ the Los Angeles Lakers 108-89 in the NBA on Sunday.A、hitB、hittedC、beatD、beated 110、——How did you sleep last night?——Like a log. Never slept ____.A、wellB、deeplyC、betterD、best 111、——The book isn’t easy for Jack to understand, is it?——____. His foreign language is far better than expected.A、No, it isn’tB、I’m afraid notC、I don’t think soD、Yes, it is 112、To read Tolstoy and ____ to the nineteenth century Russian literature are two excellent reasons for taking Professor Morrel’s course.A、to introduceB、introduceC、being introducedD、to be introduced113、You’d better not wear such ties, because they ____ three years ago.A、went onB、went offC、went overD、went out 114、——“Dear Frank, when will our wedding be?”——“Ah, when? God knows.” He said, and ____ away from her, walked rapidly away.A、turningB、turnedC、turnD、to turn 115、——Watch!——I ____ but ____ I ____ anything unusual.A、watched; have watchedB、have watched; am not seeingC、was watching; wasn’t seeingD、am watching; don’t see116、He ____ writing the paper now. He hadn’t writt en a single word when I left him ten minutes ago.A、shouldn’t beB、can’t have finishedC、can’t beD、mustn’t have finished 117、——Why are the tax collectors so busy?——Many people prefer to have their tax forms completed by a professional rather than ___.A、do it themselvesB、doing it themselvesC、to do it themselvesD、done by themselves 118、She felt sorry that she had disturbed the ____ calmness of a man she respected.A、regularB、curiousC、usualD、various119、I haven’t read ____ of his books, but judging from the one I have read I think he’s a very promising writer.A、anyB、noneC、bothD、either120、Women have ____ equal say in affairs at home.A、anyB、someC、/D、an 121、——Tomorrow ____ my birthday. I’d like you and Jane to come.——I’m not sure if she ____ free.A、will be; isB、is going to; isC、is; isD、is; will be 122、——Do you have anything in mind ____ you’d like for supper?——Well, ____ is okay with me.A、that; anythingB、which; everythingC、what; whateverD、where; something123、Parents are advised to take pressure ____ a child and give him some encouragement before an exam.A、offB、outC、fromD、away124、The generous donation from China to the sufferers in the killing Indian Ocean Quake-tsunami has ____ the Chinese people’s unselfishness and internationalism.125、My command of English is not ____ yours.A、as half asB、so half good asC、good as half asD、half so good as 126、I know the man by ____ but I have never spoken to him.A、chanceB、heartC、sightD、experience 127、____ nearly all behavior is learned behavior is a basic assumption of social scientists.A、/B、ThatC、It is acceptableD、When 128、——Mary, what would you say to a holiday for the weekend?——____. I am simply tired of life here.A、You’re taken the words out of my mouthB、Enjoy yourselfC、I can’t afford the timeD、Where should we go?129、A British man who ____ to play practical jokes ____ his own humorous art work in four major New York museums over the last two weeks.A、liked; has secretly hungB、likes; has secretly hungC、had liked; secretly hungD、has liked; secretly hung130、——Are you content with her lecture?——Nowhere near that. It ____.A、may have been goodB、couldn’t have been worseC、can’t be betterD、must be better131、Shanghai is the first city in the world ____a high-speed maglev train, from the city to Pudong Airport.A、to buildB、to be builtC、to have builtD、to have been built 132、After the 1980s, the West became Godlike to many Chinese because of ____ Westerners’ wealth, and ____ freedom to do what they wanted.A、/; /B、the; theC、the; /D、/; the133、Experience is believing. If you’d like to know what it ____ like to be a soldier in World War Ⅱ，____ the game “Brothers in Arms: Roads to Hill 30”.A、would be; tryB、was; tryC、would be; tryingD、was; trying 134、The inspector ____ his fingers over the sheet of newspaper. There were some marks on the surface of the paper.A、turnedB、setC、heldD、ran135、The size of the generation gap seems to be spreading with ____ rapid changes in technology, in education, in transportation and in communication that are taking place all over ____ globe.A、the; theB、the; /C、/; /D、/; the136、Nothing in my life has meant ____ to me as his praise.A、as muchB、moreC、that muchD、as good 137、Never in my wildest dreams ____ lead to a career in the NBA, which has allowed me to give back to my people in Africa.A、I thought the chance wouldB、I thought would the chanceC、did I think the chance wouldD、did I think would the chance 138、——May I put my luggage on the seat beside you, sir?——____.A、Sure, with pleasureB、Okay, please yourselfC、Well, never mindD、Yes, help yourself139、She’s fainted. Throw some water on her face and she’ll ____.A、come roundB、come alongC、come onD、come out 140、Small as it is, the ant is as much a creature as ____ all other animals on the earth.A、areB、isC、haveD、do 141、——How is it that you know she’s got back from the UK?——She ____ when I came out of the house this morning.A、 seemed to be passingB、happened to have passedC、chanced to be passingD、chose to be passing142、——Is there any hope of saving his life?——His injuries are extremely serious, but he’s expected to ____.A、pull inB、pull throughC、pull upD、pull over143、All the task ____ ahead of time, they decided to go on holiday for a week.A、had been finishedB、were finishedC、having been finishedD、been finished 144、——He ought to have been warned of the danger.——____, but he wouldn’t listen to me.A、yes, he ought toB、So he wasC、So was heD、So it was with him 145、Lang Ping, who is said to have started her coaching career in America, ____ volleyball in China for almost twenty years.A、playedB、have playedC、was playingD、had played146、An actor can not well play the role without life experience ____ more than a dancer can make a difference without much practice.A、anyB、noC、notD、much147、Each of the 400 people received from their boss____ gift——“Who moved my cheese?”——____ best-seller in the US——to understand how to deal with changes in their lives and work. A、the; 不填 B、a；a C、a；不填 D、the；a 148、Passenger: Look out! There’s a kangaroo wandering on the road!Driver: ____ it! That was lucky. It can damage my car really badly.A、MissingB、MissedC、To missD、Miss149、Most of the audience wondered what idea a man who’s deaf from birth can have ____ music.A、withB、inC、ofD、at 150、——Were you busy last weekend?——Very. Rather than ____ time playing cards as usual, I devoted every effort to ____ an advertisement.A、wasting; makingB、waste; makeC、to waste; makeD、a waste of; making 151、——What is the man over there?——I don’t know for sure. But I think he can be ____ but a teacher.A、anybodyB、anythingC、nobodyD、nothing152、One of the requirements for a fire is that the material ____ to its burning temperature.A、is heatedB、be heatedC、would be heatedD、do heat153、——What can I do for you, sir?——I want ____.A、a dime’s worth of candyB、candy a dime’s worthC、a dime worth of candyD、a dime-worth candy154、As the proverb ____, an enemy in disguise is a wolf in sheep’s ____.A、runs; dressB、says; clothesC、speaks; clothD、goes; clothing 155、——So you are not spending your holiday in Wuhan this year.——No, ____.A、everywhere in WuhanB、somewhere in WuhanC、somewhere but in WuhanD、anywhere but in Wuhan156、When he realized the police had seen him, the man ____ the exit as quickly as possible.A、made upB、made forC、made outD、made off 157、In the traffic accident, his father came close to ____.A、be killedB、being killedC、killD、killing 158、The heroic story that the university student had saved a peasant’s life hit the ____ in “China Youth Daily”.A、resultsB、effortsC、rewardsD、headlines 159、I don’t want to be interrupted, for my paper is due tomorrow. If ____ asks where I am.Just say I’ve gone out.A、someoneB、anyoneC、everyoneD、no one160、In ____ world, where computers rule our work and life online searches have became ____ necessity.A、a; aB、a; theC、the; aD、the; / 161、——Have you heard the new benefit system is to take effect?——Yes. That’s great, yet some worry it may ____ laziness.A、encourageB、developC、causeD、prevent 162、——Excuse me, Professor Smith, I was wondering if I could leave a quarter earlier today.——____.A、Nothing the matter.B、Sure, go aheadC、Oh, why not?D、Of course, no problem.163、——Look, it ____ again.——yeah. This is the third snow we ____ this spring.A、will snow; are havingB、has snowed; had hadC、is snowing; have hadD、snows; have had164、I invited five people to my party. Out of those five people, only John and Mary can come.____ people can’t come.A、The othersB、The otherC、OthersD、Other three 165、If you think that the illness might be serious, you should not ____ going to the doctor.A、put offB、put asideC、hold backD、hold up 166、It was only after some progress ____ in the use and development of electricity that men began to realize the importance and possibilities of magnetism.A、was madeB、would have been madeC、has been madeD、had been made 167、The central government is sparing no efforts to ____ the officials’ overuse of power to make up a healthier Party.A、keep offB、keep downC、keep outD、keep on168、Let’s go out now. It ____ any more.A、didn’t rainB、doesn’t rainC、won’t rainD、isn’t raining169、Why don’t you try on this jacket? It ____ nice on you.A、looksB、lookedC、will lookD、has looked 170、——Do you have ____ trouble finishing the work?——The work is not so difficult as you think. We have finished it already.A、anyB、noC、muchD、some171、It’s no ____ that he didn’t come.A、differenceB、importanceC、relationD、matter英语易错题组练1. The bird left its nest early______worms.The bird left its nest early, _____ worms.A. catchB. to catchC. caughtD. catching2. I don’t believe the news_____he had told us.We all believed the news _____our football team had won the match.A. thatB. that/whichC. whatD. on which3. We would like ____skating on real ice.We feel like_____skating on real ice.A. wentB. goneC. goingD. to go4. To finish so much work in so little time is_____ .To finish so little work in so much time is ______ .A. out of questionB. out of the questionC. possiblyD. impossibly5. Who is the man _____is standing there?Do you know the man_____is standing there?A. thatB. whomC. whoseD. who/that6. He is____a fool as to believe that.He is _____foolish as to believe that.A. soB. asC. suchD. too7. _____is no need for us to discuss the question again.______is no good our discussing the question again.A. ItB. ThereC. HereD. That8. He was ____good a teacher that every student loved him.He was _____ good a teacher as our class teacher.A. soB. suchC. asD. that9. After a long walk, the old man isn’t _____tired.Though he has been working since morning, he isn’t _____tired.A. a bitB. a lotC. a littleD. a few10. It is about ten days____he returned home.It was ten days ago____he left home.A. beforeB. thatC. sinceD. after。

(易错题精选)初中数学代数式真题汇编附答案解析

（易错题精选）初中数学代数式真题汇编附答案解析一、选择题1．计算的值等于（）A．1 B．C．D．【答案】C【解析】【分析】直接利用幂的乘方运算法则、积的乘方运算法则将原式变形进而得出答案．【详解】原式＝＝＝.故选C．【点睛】此题主要考查了幂的乘方运算以及积的乘方运算，正确将原式变形是解题关键．2．若2m＝5，4n＝3，则43n﹣m的值是( )A．910B．2725C．2 D．4【答案】B【解析】【分析】根据幂的乘方和同底数幂除法的运算法则求解．【详解】∵2m＝5，4n＝3，∴43n﹣m=344nm=32(4)(2)nm=3235=2725故选B.【点睛】本题考查幂的乘方和同底数幂除法，熟练掌握运算法则是解题关键. 3．计算3x2﹣x2的结果是（）A ．2B ．2x 2C ．2xD ．4x 2【答案】B【解析】【分析】根据合并同类项的法则进行计算即可得．【详解】3x 2﹣x 2=（3-1）x 2=2x 2，故选B ．【点睛】本题考查合并同类项，解题的关键是熟练掌握合并同类项法则.4．下列运算正确的是（）A ．3a 3+a 3＝4a 6B ．（a+b ）2＝a 2+b 2C ．5a ﹣3a ＝2aD ．（﹣a ）2•a 3＝﹣a 6【答案】C【解析】【分析】依次运用合并同类型、完全平方公式、幂的乘法运算即可．【详解】A .3a 3+a 3＝4a 3，故A 错误；B ．（a +b ）2＝a 2+b 2+2ab ，故B 错误；C .5a ﹣3a ＝2a ，故C 正确；D ．（﹣a ）2•a 3＝a 5，故D 错误；故选C ．【点睛】本题考查了幂的运算与完全平方公式，熟练掌握幂运算法则与完全平方公式是解题的关键．5．下列运算错误的是（）A ．()326m m =B ．109a a a ÷=C ．358⋅=x x xD ．437a a a +=【答案】D【解析】【分析】直接利用合并同类项法则以及单项式乘以单项式运算法则和同底数幂的除法运算法则化简求出即可．【详解】A 、（m 2）3=m 6，正确；B 、a 10÷a 9=a ，正确；C 、x 3•x 5=x 8，正确；D 、a 4+a 3=a 4+a 3，错误；【点睛】此题考查合并同类项法则以及单项式乘以单项式运算法则和同底数幂的除法运算法则等知识，正确掌握运算法则是解题关键．6．观察等式：232222+=-；23422222++=-；2345222222+++=-⋅⋅⋅已知按一定规律排列的一组数：502、512、522、⋅⋅⋅、992、1002．若502a =，用含a 的式子表示这组数的和是（）A ．222a a -B ．2222a a --C ．22a a -D ．22a a +【答案】C【解析】【分析】根据题意，一组数：502、512、522、⋅⋅⋅、992、1002的和为250＋251＋252＋…＋299＋2100＝＝a ＋(2＋22＋…＋250)a ，进而根据所给等式的规律，可以发现2＋22＋…＋250＝251－2，由此即可求得答案.【详解】250＋251＋252＋…＋299＋2100＝a ＋2a ＋22a ＋ (250)＝a ＋(2＋22＋…＋250)a ，∵232222+=-， 23422222++=-，2345222222+++=-，…，∴2＋22＋…＋250＝251－2，∴250＋251＋252＋…＋299＋2100＝a ＋(2＋22＋…＋250)a＝a ＋(251－2)a＝a ＋(2 a －2)a＝2a 2－a ，故选C.【点睛】本题考查了规律题——数字的变化类，仔细观察，发现其中哪些发生了变化，哪些没有发生变化，是按什么规律变化的是解题的关键.7．下列运算正确的是（）A ．a 5﹣a 3＝a 2B ．6x 3y 2÷（﹣3x ）2＝2xy 2C ．2212a 2a-= D ．（﹣2a ）3＝﹣8a 3【解析】【分析】直接利用单项式除以单项式以及积的乘方运算法则、负指数幂的性质分别化简得出答案．【详解】A 、a 5﹣a 3，无法计算，故此选项错误；B 、6x 3y 2÷（﹣3x ）2＝6x 3y 2÷9x 2＝23xy 2，故此选项错误； C 、2a ﹣2＝22a ，故此选项错误； D 、（﹣2a ）3＝﹣8a 3，正确．故选D ．【点睛】此题主要考查了单项式除以单项式以及积的乘方运算、负指数幂的性质，正确掌握相关运算法则是解题关键．8．下列运算正确的是( )A ．2235a a a +=B ．22224a b a b +=+()C ．236a a a ⋅=D ．2336()ab a b -=- 【答案】D【解析】【分析】根据合并同类项法则、完全平方公式、同底数幂乘法法则、积的乘方法则逐一进行计算即可得.【详解】A. 235a a a +=，故A 选项错误；B. 222244a b a ab b +=++()，故B 选项错误；C. 235a a a ⋅=，故C 选项错误；D. 2336()ab a b -=-，正确，故选D.【点睛】本题考查了整式的运算，涉及了合并同类项、完全平方公式、积的乘方等运算，熟练掌握各运算的运算法则是解题的关键.9．在长方形内，若两张边长分别为和（）的正方形纸片按图1，图2两种方式放置（图1，图2中两张正方形纸片均有部分重叠），长方形总未被这两张正方形纸片覆盖的部分用阴影表示，若图1中阴影部分的面积为，图2中阴影部分的面积和为，则关于，的大小关系表述正确的是（）A．B．C．D．无法确定【答案】A【解析】【分析】利用面积的和差分别表示出，，利用整式的混合运算计算他们的差即可比较.【详解】=（AB-a）·a+（CD-b）（AD-a）=（AB-a）·a+（AD-a）（AB-b）=（AB-a）（AD-b）+（CD-b）（AD-a）=（AB-a）（AD-b）+（AB-b）（AD-a）∴-=（AB-a）（AD-b）+（AB-b）（AD-a）-（AB-a）·a-（AD-a）（AB-b）=（AB-a）(AD-a-b)∵AD＜a+b，∴-＜0，故选A.【点睛】此题主要考查此题主要考查整式的运算，解题的关键是熟知整式的乘法法则.10．下列运算正确的是（）A．x3+x5=x8 B．(y+1)(y-1)=y2-1 C．a10÷a2=a5 D．(-a2b)3=a6b3【答案】B【解析】【分析】直接利用合并同类项法则以及积的乘方运算法则、整式的乘除运算分别计算得出答案．【详解】A、x3+x5，无法计算，故此选项错误；B、（y+1）（y-1）=y2-1，正确；C、a10÷a2=a8，故此选项错误；D、（-a2b）3=-a6b3，故此选项错误．故选：B ．【点睛】本题考查了合并同类项以及积的乘方运算、整式的乘除运算，正确掌握相关运算法则是解题的关键．11．若55+55+55+55+55＝25n ，则n 的值为（）A ．10B ．6C ．5D ．3【答案】D【解析】【分析】直接利用提取公因式法以及幂的乘方运算法则将原式变形进而得出答案．【详解】解：∵55+55+55+55+55=25n ，∴55×5=52n ，则56=52n ，解得：n =3．故选D ．【点睛】此题主要考查了幂的乘方运算，正确将原式变形是解题关键．12．下列计算正确的是（）A ．a•a 2＝a 2B ．（a 2）2＝a 4C ．3a+2a ＝5a 2D ．（a 2b ）3＝a 2•b 3【答案】B【解析】本题考查幂的运算．点拨：根据幂的运算法则．解答：2123a a a a +⋅== ()22224a a a ⨯== 325a a a += ()3263a b a b = 故选B ．13．下列图形都是由同样大小的五角星按照一定规律所组成的，按此规律排列下去，第n 个图形中五角星的个数为（）A ．31n -B ．3nC ．31n +D ．32n +【答案】C【解析】【分析】根据前4个图形中五角星的个数得到规律，即可列式得到答案.【详解】观察图形可知：第1个图形中一共是4个五角星，即4311=⨯+，第2个图形中一共是7个五角星，即7321=⨯+，第3个图形中一共是10个五角星，即10331=⨯+，第4个图形中一共是13个五角星，即13341=⨯+，L ，按此规律排列下去，第n 个图形中一共有五角星的个数为31n +，故选：C.【点睛】此题考查图形类规律的探究，观察图形得到五角星的个数的变化规律并运用解题是关键.14．已知单项式2m 13a b -与n 7a b -互为同类项，则m n +为( )A ．1B ．2C ．3D ．4【答案】D【解析】【分析】根据同类项的概念求解．【详解】解：Q 单项式2m 13a b -与7a b n -互为同类项， n 2∴=，m 11-=，n 2∴=，m 2=．则m n 4+=．故选D ．【点睛】本题考查了同类项的知识，解答本题的关键是掌握同类项定义中的两个“相同”：相同字母的指数相同．15．下列计算正确的是（）A ．23a a a ⋅=B ．23a a a +=C ．()325a a =D ．23(1)1a a a +=+【答案】A【解析】【分析】根据合并同类项的法则，同底数幂的乘法，单项式乘多项式以及幂的乘方的知识求解即可求得答案．【详解】A 、a•a 2=a 3，故A 选项正确；B 、a 和2a 不是同类项不能合并，故B 选项错误；C 、（a 2）3=a 6，故C 选项错误；D 、a 2（a+1）=a 3+a 2，故D 选项错误．故答案为：A ．【点睛】本题主要考查了合并同类项的法则，同底数幂的乘法，单项式乘多项式以及幂的乘方的知识，解题的关键是熟记法则．16．已知多项式x -a 与x 2+2x -1的乘积中不含x 2项，则常数a 的值是（）A ．-1B ．1C ．2D ．-2【答案】C【解析】分析：先计算（x ﹣a ）（x 2+2x ﹣1），然后将含x 2的项进行合并，最后令其系数为0即可求出a 的值．详解：（x ﹣a ）（x 2+2x ﹣1）=x 3+2x 2﹣x ﹣ax 2﹣2ax +a=x 3+2x 2﹣ax 2﹣x ﹣2ax +a=x 3+（2﹣a ）x 2﹣x ﹣2ax +a令2﹣a =0，∴a =2．故选C ．点睛：本题考查了多项式乘以多项式，解题的关键是熟练运用运算法则，本题属于基础题型．17．已知x=2y+3，则代数式9-8y+4x 的值是（）A ．3B ．21C ．5D ．-15【答案】B【解析】【分析】直接将已知变形进而代入原式求出答案.【详解】解:∵x=2y+3∴x-2y=3∴98494(2y x y x -+=--⨯)=9-4(-3)=21故选：B【点睛】此题主要考查了整式的加减以及代数式求值，正确将原式变形是解题关键.18．下面的图形都是由同样大小的棋子按照一定的规律组成，其中第①个图形有1颗棋子，第②个图形有6颗棋子，第③个图形有15颗棋子，第④个图中有28颗棋子，…，则第6个图形中棋子的颗数为（）A ．63B ．64C ．65D ．66【答案】D【解析】【分析】根据图形中棋子的个数找到规律，从而利用规律解题．【详解】解：∵通过观察可以发现：第1个图形中棋子的个数为()11211=⨯⨯-；第2个图形中棋子的个数为()62221=⨯⨯-；第3个图形中棋子的个数为()153231=⨯⨯-；第4个图形中棋子的个数为()284241=⨯⨯-；L L第n 个图形中棋子的个数为()21n n -∴第6个图形中棋子的个数为()626166⨯⨯-=．故选：D【点睛】本题考查了图形变化规律的问题，能找出第n 个图形棋子的个数的表达式是解题的关键．19．如图，下列各三角形中的三个数之间均具有相同的规律，根据此规律，最后一个三角形中y与n之间的关系是（）A．y=2n+1 B．y=2n+n C．y=2n+1+n D．y=2n+n+1【答案】B【解析】【详解】∵观察可知：左边三角形的数字规律为：1，2，…，n，右边三角形的数字规律为：2，，…，，下边三角形的数字规律为：1+2，，…，，∴最后一个三角形中y与n之间的关系式是y=2n+n.故选B．【点睛】考点：规律型：数字的变化类．20．下列命题正确的个数有（）①若 x2+kx+25 是一个完全平方式，则 k 的值等于 10；②一组对边平行，一组对角相等的四边形是平行四边形；③顺次连接平行四边形的各边中点，构成的四边形是菱形；④黄金分割比的值为≈0.618.A．0 个B．1 个C．2 个D．3 个【答案】C【解析】【分析】根据完全平方式的定义，黄金分割的定义，平行四边形的判定，菱形的判定即可一一判断；【详解】①错误．x2+kx+25是一个完全平方式，则 k 的值等于±10 ②正确．一组对边平行，一组对角相等，可以推出两组对角分别相等，即可判断是平行四边形；③错误．顺次连接平行四边形的各边中点，构成的四边形是平行四边形；④正确．黄金分割比的值为≈0.618；故选C．【点睛】本题考查完全平方式的定义，黄金分割的定义，平行四边形的判定，菱形的判定等知识，解题的关键是熟练掌握基本知识．。

(易错题精选)初中数学有理数的运算难题汇编附答案解析(1)

（易错题精选）初中数学有理数的运算难题汇编附答案解析(1)一、选择题1．0000084=8.4×10-6故选B.【点睛】本题考查用科学记数法表示较小的数，一般形式为a×10-n，其中1≤|a|＜10，n为由原数左边起第一个不为零的数字前面的0的个数所决定．2．下列说法中，正确的是（）A．在数轴上表示-a的点一定在原点的左边B．有理数a的倒数是1 aC．一个数的相反数一定小于或等于这个数D．如果a a=-，那么a是负数或零【答案】D【解析】【分析】根据实数与数轴的对应关系、倒数、相反数、绝对值的定义来解答.【详解】解：A、如果a<0，那么在数轴上表示-a的点在原点的右边，故选项错误；B、只有当a≠0时，有理数a才有倒数，故选项错误；C、负数的相反数大于这个数，故选项错误；D、如果a a=-，那么a是负数或零是正确.故选D.【点睛】本题考查了数轴、倒数、相反数、绝对值准确理解实数与数轴的定义及其之间的对应关系.倒数的定义：两个数的乘积是1，则它们互为倒数；相反数的定义：只有符号不同的两个数互为相反数；绝对值的性质：一个正数的绝对值是它本身；一个负数的绝对值是它的相反数；0的绝对值是0.3．2019-的倒数是（）A．2019 B．－2019 C．12019D．12019-【答案】C【解析】【分析】先利用绝对值的定义求出2019-，再利用倒数的定义即可得出结果.2019-=2019,2019的倒数为1 2019故选C【点睛】本题考查了绝对值和倒数的定义，熟练掌握相关知识点是解题关键.4．下列运算正确的是（）A．a5⋅a3 = a8B．3690000=3.69×107C．(－2a)3 =－6a3D．02016=0【答案】A【解析】【分析】分别根据同底数幂的乘法，科学记数法，幂的乘方和积的乘方，零指数幂求出每个式子的值，再判断即可．【详解】A、结果是a8，故本选项符合题意；B、结果是3.69×106，故本选项不符合题意；C、结果是-8a3，故本选项不符合题意；D、结果是1，故本选项不符合题意；故选：A．【点睛】此题考查同底数幂的乘法，科学记数法，幂的乘方和积的乘方，零指数幂，能正确求出每个式子的值是解题关键.5．据央视网报道，2019年1～4月份我国社会物流总额为88.9万亿元人民币，“88.9万亿”用科学记数法表示为( )A．138.8910⨯B．128.8910⨯C．1288.910⨯D．118.8910⨯【答案】A【解析】【分析】利用科学记数法的表示形式进行解答即可【详解】6．计算﹣6+1的结果为（）A．﹣5 B．5 C．﹣7 D．7【答案】A【解析】【分析】根据有理数的加法法则，|﹣6|＞|1|，所以结果为负号，并把它们的绝对值相减即可.解：﹣6+1＝﹣（6﹣1）＝﹣5故选：A．【点睛】本题考查了有理数的加法，注意区别同号相加与异号相加，把握运算法则是关键．7．计算12+16+112+120+130+……+19900的值为（）A．1100B．99100C．199D．10099【答案】B【解析】分析：直接利用分数的性质将原式变形进而得出答案．详解：原式=11111 1223344599100 ++++⋯+⨯⨯⨯⨯⨯=111111112233499100 -+-+-+⋯+-，=1-1 100=99 100．故选B．点睛：此题主要考查了有理数的加法，正确分解分数将原式变形是解题关键．8．我国是世界上严重缺水的国家之一，目前我国每年可利用的淡水资源总量为27500亿米3，人均占有淡水量居全世界第110位，因此我们要节约用水，27500亿用科学记数法表示为（）A．275×104 B．2.75×104 C．2.75×1012 D．27.5×1011【答案】C．【解析】试题解析：将27500亿用科学记数法表示为：2.75×1012．故选C．考点：科学记数法—表示较大的数．9．已知：||2||3||a b b c c amc a b+++=++，且abc＞0，a+b+c＝0．则m共有x个不同的值，若在这些不同的m值中，最大的值为y，则x+y＝（）A．4 B．3 C．2 D．1【答案】B【解析】【分析】根据绝对值的意义分情况说明即可求解．【详解】∵abc＞0，a+b+c=0，∴a、b、c为两个负数，一个正数，a+b=﹣c，b+c=﹣a，c+a=﹣b，m23c a bc a b---=++，∴分三种情况讨论：当a＜0，b＜0，c＞0时，m=1﹣2﹣3=﹣4，当a＜0，c＜0，b＞0时，m=﹣1﹣2+3=0，当a＞0，b＜0，c＜0时，m=﹣1+2﹣3=﹣2，∴x=3，y=0，∴x+y=3．故选：B．【点睛】本题考查了有理数的混合运算和绝对值，解答本题的关键是分类讨论．10．为应对疫情，许多企业跨界抗疫，生产口罩．截至2月29日，全国口罩日产量达到116000000只．将116000000用科学记数法表示应为（）A．611610⨯B．711.610⨯C．71.1610⨯D．81.1610⨯【答案】D【解析】【分析】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≥10时，n是正数；当原数的绝对值＜1时，n是负数．【详解】将116000000用科学记数法表示应为1.16×108．故选：D．【点睛】此题考查科学记数法的表示方法．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，表示时关键要正确确定a的值以及n的值．11．-2的倒数是（）A．-2 B．12-C．12D．2【答案】B【解析】【分析】根据倒数的定义求解.【详解】-2的倒数是-1 2故选B【点睛】本题难度较低，主要考查学生对倒数相反数等知识点的掌握12．大量事实证明,治理垃圾污染刻不容缓.据统计,全球每分钟约有8500000吨污水排入江河湖海,这个排污量用科学记数法表示为()A．8.5×105 B．8.5×106C．85×105 D．85×106【答案】B【解析】【分析】根据科学记数法的表示形式：a×10n，其中1≤|a|＜10，n为整数．解答即可.【详解】8500000=8.5×106，故选B.【点睛】此题考查科学记数法的表示方法．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，表示时关键要正确确定a的值以及n的值．13．一年之中地球与太阳之间的距离随时间而变化，1个天文单位是地球与太阳之间的平均距离，即1.496亿km．用科学记数法表示1.496亿是（）A．71.49610⨯B．714.9610⨯C．80.149610⨯D．81.49610⨯【答案】D【解析】分析：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．详解：数据1.496亿用科学记数法表示为1.496×108．故选D ．点睛：本题考查了科学记数法的表示方法．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，表示时关键要正确确定a 的值以及n 的值．14．2019年3月3日至3月15日，中国进入“两会时间”，根据数据统计显示，2019年全国两会热点传播总量达829.8万条，其中数据“829.8万”用科学记数法表示为（） A ．8.298×107B ．82.98×105C ．8.298×106D ．0.8298×107【答案】C【解析】【分析】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．【详解】数据“829.8万”用科学记数法表示为8.298×106．故选C ．【点睛】此题考查科学记数法的表示方法．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，表示时关键要正确确定a 的值以及n 的值．15．6万亿=296000000000000=2.96×1013．故选B ．【点睛】本题考查了科学记数法的表示方法．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，表示的关键是要正确确定a 的值以及n 的值．16．若30,a -=则+a b 的值是（）A ．2B 、1C 、0D 、1-【答案】B【解析】试题分析：由题意得，3﹣a=0，2+b=0，解得，a=3，b=﹣2，a+b=1，故选B ．考点：1．非负数的性质：算术平方根；2．非负数的性质：绝对值．17．预计到2025年，中国5G 用户将超过460 000 000，将460 000 000用科学计数法表示为（）A ．94.610⨯B ．74610⨯C ．84.610⨯D ．90.4610⨯【解析】【分析】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．当原数绝对值大于10时，n 是正数；当原数的绝对值小于1时，n 是负数．【详解】460 000 000=4.6×108．故选C ．【点睛】此题考查科学记数法的表示方法．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，表示时关键要正确确定a 的值以及n 的值．18．下列用科学记数法表示正确的是（）A ．10.000567 5.6710-=-⨯B ．40.0012312.310=⨯C ．20.0808.010-=⨯D ．5696000 6.9610--=⨯【答案】C【解析】分析: 绝对值小于1的正数也可以利用科学记数法表示，一般形式为a×10-n ，与较大数的科学记数法不同的是其所使用的是负指数幂，指数由原数左边起第一个不为零的数字前面的0的个数所决定.详解: A. 40.000567 5.6710--=-⨯,故错误;B. 30.0012312.310,-=⨯故错误;C. 20.0808.010-=⨯,正确;D. 5696000 6.9610-=⨯,故错误.故选：C.点睛: 本题考查用科学记数法表示较小的数，一般形式为a×10-n ，其中1≤|a|＜10，n 为由原数左边起第一个不为零的数字前面的0的个数所决定.19．计算(-2)100+(-2)99的结果是( )A ．2B ．2-C ．992-D ．992【答案】D【解析】解：原式=（﹣2）99[（﹣2）+1]=﹣（﹣2）99=299．故选D ．20．已知资阳市某天的最高气温为19℃，最低气温为15℃，那么这天的最低气温比最高气温低（）A ．4℃B ．﹣4℃C ．4℃或者﹣4℃D ．34℃【解析】【分析】所求的数值就是最高气温与最低气温的差，利用有理数的减法法则即可求解．【详解】19﹣15＝4（℃）答：这天的最低气温比最高气温低4℃．故选A．【点睛】本题主要考查有理数的减法法则：减去一个数等于加上这个数的相反数．这是需要熟记的内容．。

初一上册人教版语法知识-英语单项选择(50题)的易错题汇编附答案含答案

初一上册人教版语法知识-英语单项选择（50题）的易错题汇编附答案含答案一、选择题1．It was the dream that he would make ______ good fortune on the international stages that made Lang Lang decide to go to the USA for ______ further study.A．a, a B．/, the C．a, / D．the, the 2．Nokia, _______ world’s largest mobile phone producer, is going to found _______ new research center in China.A．a; a B．a; the C．the; the D．the; a3．_____ Nantong today is more beautiful than before.Mr.Jackson said he would visit it ____ third time.A．The ; a B．The ; the C．/; the D．/; a二、选择题4．—This book on Yancheng’s history is interesting. I’d like______. Where did you buy it, Tom? —In the Amazon Bookstore.A．it B．this C．that D．one三、选择题5．—Michael, could you tell me the way to Haian Museum?—Sorry. But you can download a map app on your phone that can show you ________ and guide you to where you want to go.A．conversation B．location C．invention D．introduction四、选择题6．There’s a ________ feeling that a high price means good quality.A．sudden B．joyful C．hard D．general 7．Thanks a lot for offering such _______ to me in my research.A．usual advice B．important advice C．a usual trip D．valuable trip五、选择题8．—You look frightened, what’s up?— A terrible accident happened this morning. A truck was running fast when an old man was about to cross the road. I bet he will not live ________ the night.A．along B．away C．through D．in9．If your temperature is_______37.3°, you should go to the doctor instead of going to school. A．above B．against C．under D．below六、选择题10．The meeting was supposed t o ________ on Tuesday, but we’ve had to put it off.A．turn on B．turn out C．take place D．take up11．— Hi, Simon! You look so excited. What happened?—We won the football match, and the result ________ to be better than expected.A．turned out B．found out C．worked out D．came out12．—I ________ reading English every morning.—Yes, English is very important and it ________ the first language in England and some othercountries.A．used to; is used by B．used to; is used asC．am used to; is used as D．am used to; is used by七、选择题13．You _________ smoke here! Look at the sign. It says "No smoking".A．needn't B．mustn't C．can D．may14．The boy is very brave．I ________ he ________ the tall tree．A．dare say; dares to climbB．dare to say; dare climbingC．dare saying; dares climbD．dare to say; dares climbed15．My bike was broken yesterday，so I____walk home．A．might B．had to C．must D．could 16．—Would you please________in that way? That’s not safe!—Sorry. I won’t do it any more.A．not driving B．not to drive C．no driving D．not drive八、选择题17．— The sky is blue and I can smell the flowers.— ________ great fun it is to go spring outing!A．How B．How a C．What D．What a 18．Look! ________ the roller coaster________!A．How high speed; is moving B．What high speed; is movingC．How high speed; is moving at D．What high speed; is moving at19．―________ crowded Changwu Road is!―Yes, because the number of cars has kept ________ greatly since April.A．What a; rising B．How a; raising C．What; raising D．How; rising 20．"__________ you've made! But you should still work hard, "the teacher said to the boy. A．What great progress B．How a big mistakeC．What a big mistake D．How great progress九、选择题21．一I love these hair clips. are they?一They are ten yuan.A．How many B．How much C．How old D．How heavy 22．－ will the invitations be sent to our guests?－In three days.A．How often B．How soon C．How long D．How far十、选择题23．The superheroes, such as Spider Man and Iron Man, ________ by Stan Lee when he was alive.A．are created B．have been created C．will be created D．were created十一、选择题24．I ______ for Shanghai this Saturday, so I want to know when the earliest plane ______. A．leave; takes off B．am leaving; takes offC．leave; is taking off D．am leaving; is taking off25．—Where’s Kelly, Mum?—She ________ a poster for the community in her bedroom.A．makes B．will make C．made D．is making 26．—Tom, where's dad?—Oh, he ________ the flowers in the garden.A．waters B．is watering C．watered D．has watered十二、选择题27．Speak louder, __________ everyone can understand you.A．so B．or C．for D．but28．— Excuse me. Do you have a table for two?—I’m sorry, there aren’t any seats now. Would you mind waiting a while?A．so B．or C．and D．but 29．—The brown jacket is nice, ________ it doesn’t look good on me.—Why not try on the blue one? I think blue suits you fine.A．and B．so C．but D．or十三、选择题30．—Do you know________ ?—Tomorrow afternoon.A．when will the headmaster give us a talkB．where will the headmaster give us a talkC．when the headmaster will give us a talkD．where the headmaster will give us a talk十四、选择题31．—How can I get along well with the local people if I go to Germany?—________.A．The early bird catches the worm B．It never rains but it poursC．When in Rome, do as the Romans do D．A friend in need is a friend indeed 32．You should do more and talk less. Actions speak louder than words.A．What you do isn’t important.B．What you do is as important as you say. C．What you do is more important than what you say. D．What you do is less important than you say.33．---All the people of Taizhou need to work together to make our city more beautiful.---That’s it . __________.A．Practice makes perfectB．Many hands make light work.C．When in Rome, do as the Romans doD．A friend in need is a friend indeed.34．—Is the air pollution getting better these days?—No. ________ , water in the rivers nearby is becoming worse and worse. Can you find out the reason?A．It never rains but it pours B．A miss is as good as a mileC．The early bird catches the worm D．Burn the candle at both ends十五、选择题35．—It’s been a wonderful party. Thank you very much?—- ________________.A．With pleasure B．No , thanks C．It’s OK D．I’m glad you enjoyed it .十六、选择题36．It's impolite to keep someone________ for a long time.A．wait B．to wait C．waiting D．have waited 37．Bad luck! The film star had her leg ________ while playing a part in a film.A．to break B．breaking C．bread D．broken38．—Is there anything amazing in today’s newspaper?—Yes. By using ordinary computers, NASA scientists are busy________ at home to control a space rover(天体登陆车）on the Red Planet. .A．to programme B．programming C．programme D．with programming 39．---You have to work very hard in your job, don’t you?----Yes, but I don’t mind that. I _____ hard.A．used to work B．am used to workC．am used work D．am used to working40．— Baby, would you mind ________ me cook the fish?—Of course not. I can’t wait ________ it!A．help; taste B．helping; taste C．help; to taste D．helping; to taste 41．The way our students thought of ________ the classroom clean and tidy proved to be very useful.A．to keep B．keeping C．kept D．keeps十七、选择题42．—Will your cousin go to Guiyang for the summer holiday?—In fact, he ________ Guiyang since he graduated.A．has gone to B．has been to C．has been in D．went to 43．Both his parents look sad. Maybe they _________ what's happened to him.A．will know B．know C．have known D．are knowing 44．Since Tencent released Wechat, it ________ one of the most popular apps in the world. A．became B．has become C．has been D．was十八、选择题45．-Hi, Lucy! What's the schedule for tomorrow?-Let me check．You an appointment with Thomas at three o'clock．A．were having B．haveC．had D．have had46．Around two o’clock every night, Sue will start talking in her dream. It somewhat ________ us.A．bothers B．had bothered C．would bother D．bothered 47．—Madam, look at the sign. You are not allowed to sit in this game area for kids.—Sorry, I ________ it. I will go somewhere else.A．don’t notice B．didn’t notice C．haven’t noticed D．wasn’t noticed 48．— Will your younger cousin go for a picnic this Children’s Day?—If I don’t go, ________.A．so does he B．so will he C．neither does he D．neither will he十九、选择题49．—Did you stay at the party for a long time last night?—Yes. I stayed there ________ the party was over.A．until B．since C．when D．if50．________ Jane couldn’t see his face, she could tell by his voice that he was a middle-aged man.A．Unless B．Although C．If D．Until【参考答案】***试卷处理标记，请不要删除一、选择题1．C解析：C【解析】本题考查冠词。

高考单选易错题、难题、好题题型专项辅导(附答案)(2021年整理)

高考单选易错题、难题、好题题型专项辅导(附答案)(word版可编辑修改) 编辑整理：尊敬的读者朋友们：这里是精品文档编辑中心，本文档内容是由我和我的同事精心编辑整理后发布的，发布之前我们对文中内容进行仔细校对，但是难免会有疏漏的地方，但是任然希望（高考单选易错题、难题、好题题型专项辅导(附答案)(word版可编辑修改)）的内容能够给您的工作和学习带来便利。

同时也真诚的希望收到您的建议和反馈，这将是我们进步的源泉，前进的动力。

本文可编辑可修改，如果觉得对您有帮助请收藏以便随时查阅，最后祝您生活愉快业绩进步，以下为高考单选易错题、难题、好题题型专项辅导(附答案)(word版可编辑修改)的全部内容。

高考单选易错题、难题、好题题型专项辅导（附答案）1。

By the time you arrive in London， we _____ in Europe for two weeks。

A. shall stayB. have stayed C。

will have stayed D. have been staying2. I appreciated ____ the opportunity to study abroad two years ago.A。

having been given B. having given C. to have been given D. to have given3. Living in the central Australian desert has its problems， _____ obtaining water is not the least。

A。

of which B. for what C. as D。

whose4. The heart is ____ intelligent than the stomach， for they are both controlled by the brain.A. not so B。

初中英语易错题精选（附答案）

初中英语易错题精选（附答案）1.I spend much more time playing basketball than I ______ for my lessons.A. spend to prepareB. spend prepareC. do to prepareD. do preparing2. ----- What did the woman ask just now?----- She asked ___________________.A. who was I waiting forB. where I liveC. how she can get to the post officeD. whether she could help to find the post office3. ______ the day went on, the weather got worse.A. WithB. SinceC. WhileD. As4. Mother was worried because little Alice was ill, especially _____ Father was away in France.A. asB. thatC. duringD. if5. It is ____________ that we’d like to go out for a walk.A. a lovely dayB. too lovely a dayC. so lovely a dayD. such a lovely day 答案：D D D A C6. Some passengers were walking through one of the big halls at Paris’ Charles De Gaulle Airport ________ the whole roof fell down.A. whileB. as soon asC. whenD. after7. “No one runs as fast as John in his class.” The sentence means ______________.A. John runs faster than any student in his classB. John runs more slowly than any other student in his classC. John runs as fast as other student in his classD. John runs fastest in his class8. Little boy _____ he was, he had learned advanced mathematics.A. asB. althoughC. butD. because9. ________ he studied in the university, he has made much progress in the study of EnglishA. WhileB. WhenC. SinceD. After10. ----- Mom, I am always worrying about too many things these days.----- Oh, dear! Maybe you should _______ taking a trip.A. expectB. suggestC. imagineD. consider答案：C D A C D11. She is one of the workers who _______ hard.A. workB. worksC. workingD. is working12. Is the toy ______ you bought in Shanghai for your little brother?A. thatB. whichC. the oneD. /13. There is no dictionary ______ you can find everything.A. thatB. whichC. whereD. in that14. He doesn’t know _______ is _______ he was born.A. that; whereB. that; whatC. where; thatD. what; where15. ------ I misspelt a word here in the sentence.------ Well, that’s _______ you were mistaken.A. whenB. whatC. whereD. why答案：A C C A C16. _______ we have seen is quite different from _______ we have heard.A. That; thatB. What; thatC. That; whatD. What; what17. Wait a moment, please. I’m checking if Mr. Smith _______ free tomorrow.A. isB. beingC. to beD. will be18. You are the _______ person I’m looking for.A. veryB. soC. justD. quite19. Jack seems ________ than you ________ ready for the exam.A. busy; to getB. much busier; gettingC. busier; to getD. more busier; getting20. ----- How long _______ you _______ in Beijing last year?----- About two weeks.A. did; stayB. have; stayedC. do; stayD. will; stay答案：D D A B A21. ----- What’s your plan for this weekend?----- _______ the park.A. VisitB. VisitingC. To visitD. I visit22. ----- _______ do you call chicks before they’re born?----- Eggs, I think.A. WhatB. HowC. WhyD. When23. What happens to the children after they leave this school?A. They do the same things as children from other school.B. They have problems getting into college or getting a job.C. They usually do very unusual jobs.D. They are not successful in their business.24. It’s report ed that the railway station _______ at the end of this year.A. has been completedB. is completedC. was completedD. will be completed25. ----- Have you got _______ e-mail address?----- Yes. _______ is tom234@/doc/af12601798.html,.A. a; ItB. /; MineC. an; MineD. the; It答案：C A C D C26. Remember: all the stories for the English writing competition be given a title.A. mustB. canC. mightD. need27. It’s wrong you to keep the audience for you outside the gate.A. for; waitB. for; waitingC. of; waitingD. of; wait28.It is any wonder that his friend doesn’t like watching television much.A. noB. almostC. nearlyD. hardly29. -----You don’t look very . Are you ill?----- No, I’m just a bit tired.A. goodB. wellC. strongD. healthy30. Sometimes it was a bit boring to work there because there wasn’t always much to do.A. suchB. thatC. more答案：A C D B B31. He was caught _______ something from the shop yesterday.A. stolenB. to stealC. to be stolenD. stealing32. After class, the students went out of the classroom one by one, but only Mary _______.A. leftB. had leftC. was leftD. was leaving33. It was the third time that she _______ him at the same place.A. had metB. has metC. would meetD. met34. Could you tell us if it snows in winter in New Zealand.____________________ .A. Yes, I know about itB. Yes, I’m coming to thatC. No, you needn’t know itD. No, you should study geography hard35. _______ UN report says that the world’s population is over six billion now.A. /B. TheD. A答案：D C A B D36. It is natural for _______ to feel that way in China.A. studentsB. teachersC. childrenD. parents37. -----Hello!----- Hello! is Kitty. Her Chinese name is Zhong Li.A. ThatB. ThisC. SheD. Her38. Why do you like your English teacher? Because he always treat us hisfriends.A. withB. forC. asD. like39. You can write your name on one side of the card and write your address on side.A. anotherB. otherC. othersD. the other40. She doesn’t have time to look at before the dresser.A. othersB. herC. clothesD. things答案：D B C D B41. In her letters she asked them to decide a day for mothers.A. bothB. allC. everyD. only her42. What music does he often .A. listen toB. listenC. listensD. listens to43. Really? It just sounds to be true.A. so wellB. too goodC. good enoughD. too well44.They are going to have a picnic next week.A. sometimeB. some timeC. sometimesD. some times45. Most young people find exciting to watch a football match.A. itB. thisC. thatD. one答案：B A B A A46. He’s already well again, he?A. hasn’tB. wasn’tC. isn’tD. doesn’t47. How about going to school by boat, Li Lei? Good idea. It is!A. How a great funB. How great funC. What a great funD. What great fun48. She is going to get married John on New Year’s Day. They aretheir twenties.A. to; inB. with; inC. to; atD. with; at49. We should do the teacher told us.A. becauseB. likeC. asD. since50. Could you tell me to go to Hainan by air? Just a minute, please.A. how much does it costB. how much did it costC. how much it costD. how much it costs答案：C D A C D51. Usually, Betty in colorful T-shirt in summer.A. wearsB. is dressedC. is wearingD. dressed52. Look, Tom a book in his hand and he very happy.A. has; looksB. is having; lookC. is having; is lookingD. has; is looking53. Fish my favourite food but my parents don’t like .A. is; themB. are; themC. is; itD. are; it54. ------ ?-----This is Jimmy speaking.A. May I speak to JaneB. Who are youC. Who’s thatD. Are you Jimmy speaking55. Do you have any money in your pocket? I’m afraid I have .A. notB. no oneC. noneD. much答案:B A C C C56. of art can you see on the wall! .A. How much work; NoneB. How many works; NoneC. How much work; No oneD. How many works; No one57. -----Do you want to the English Club?-----Yes. I want to you in different activities to make my English better.A. join; joinB. join in; join inC. join; join inD. join in; join58. -----How nice the fish !-----Yes. But fish not easy to catch.A. tastes; areB. taste; areC. tastes; isD. taste; is59. -----Can I have some milk, Mum?-----Oh, I’m sorry. There is left at home.A. fewB. a fewC. littleD. a little60. ----- do you go to the cinema? ----- Never.A. How many timesB. How longC. How oftenD. How soon答案：B A A C C1. Last week, my mother bought two pairs of shoes for $50.2. The sports meeting is likely (可能的) to take place next week.3. The boy student sits in the middle (中央) of the classroom.4. ----- What would you like for a drink?----- Anything will do (do). I don’t care.5. Liu Xiaoqing is an uncommon (非凡的) actress and she has many fans.6. ---- Has Li Jun finished his report?----- I have no idea. He was writing (write) the report last night.7. The charity show will be the hottest event (活动) next week.8. Her star sign shows that she is probably (或许) a careless person.9. The film star hopes to be left (leave) alone when she is on holiday in Hawaii.10. The internet is good for us and can bring us the up-to-date news.11. Can you tell me who was presented (授予) with the MVP in last year’s NBA.12. We drove round the town in search (搜寻) of a cheap hotel.13. How many salesmen (售货员) are working in that shopping mall?14. Our food is running (run) out. Let’s buy some before there’s none left.15. Stress is a normal part of life and usually comes from everyday study and work.16. The sights (名胜) made every visitors excited and they didn’t want to leave.17. The old man is sitting among the children and telling a story.18. The flowers and applause are always around the winners.19. There’s nothing but a table in the room.20. She has sent for a doctor.21. I am pleased that he gladly accepted (接受) our invitation.22. They are aware (意识到的) of the dangers.23. Why do you think you did so badly (糟糕地) in your test?24. If the sky is clear, there’s no rain or clouds and you can see very far.25. The mall is open (open) from 9 a.m. to 10 a.m.26. Spring is the best season for growing trees and flowers.27. Do you often go climbing the mountain with your parents?28. Look at the TV. President Hu Jintao meeting with president Obama.29. Taking a plane is like a bird flying in the sky.30. When he gets home, he always goes straight (径直) to the dining room for food.31. My mother always tells me not to be (not be) late for class.32. How happy we are to meet (meet) you here!33. Amy lives nearby in the centre of the city.34. He took off his clothes and lay (lie) down to sleep.1.即使雨下得很大，他们仍然在田里干活。

人教版七年级下册英语易错题练习(附答案)

人教版七年级下册英语易错题练习(附答案)人教版七年级下册英语易错题练（附答案）一、选择填空。

() 1. How does the idea to you?A. XXXXXX() 2. The dish good.A. looksB. feelsXXX() 3. The baby is learning to .A. XXXXXX() 4. We music teachers, but we need art teachers.A. needn’tB. can’t needXXX() 5. One day Tom Mike that Bei dai he Kids Summer Campneeds helpA. XXXXXX() 6. If you don’t wantto go shopping, I won’t.A. alsoB. tooC. XXX() 7. Are you good kids or old people?A. toB. withXXX() 8.–Do you know some one who can Chinese kung fu?-I have no idea.A. XXXC. doesD. do() 9. He can football now.A. XXXC. to playD. play() 10.–Do you often ?-Yes, I do. I play them well.A. play the trumpetB. pay baseballC. play the guitarD. play computer games() 11. The boy often a cold in XXX hasC. catchD. carry() 12. You’d better do morningeveryday. It’s good tohave lots of .A. exercise; exerciseB. exercises; exercisC. exercise; exercisesD. exercises; exercises() 13. They go to school XXX’t; XXX’t; onC. aren’t; inD. not; in() 14.–Lucy, your coat, please.–It’s time to go to school.A. get dressedB. put onC. wearD. dress() 15. His grandparents often go out forin the early morning.A. XXXXXX() 16. My home is farfrom our school. It’s aboutwalk, so Itakethe bus to school.A. XXX-minutesXXX’() 17. You can stay at home go outto play.A. either; orB. both; andC. neither; norD. Both A and B() 18. Lucy Lily may go dancingwith you, because they are not allowedto go out on school nights.A. XXX; XXX; norC. Both; andD. Not only; but also() 19.–I’m XXX.–Oh, I have no idea .A. XXXXXX() 20. You can go to that new restaurant,because food there tastes .A. wellB. badXXX deliciously() 21. He often listens to all kinds of music sohe shows good in music.A. XXXXXX() 22. Lucy and Lily want to go to thepark?A. DoB. DoesC. IsD. Are() 23. I often watch TV, but sometimes I XXX.A. to doB. doXXX have() 24.–How do they get toschool?- .A. They by bike to school.B. they XXXC. They get to school by the bike.D. XXX.() 25.–How do you usually go to school?-I usually to go to school.A. take busB. take a busXXX() 26.–How far is it from here to the park?-It’s aboutride.A. XXX XXX minutesC. fifteen minutes’D. fifteen-minutes() 27. it take you to go to work on foot?A. How long isB. How many times doesC. How many hours isD. How long does() 28. old people exercise in the newpark every day ,becauseit is very beautiful.A. XXX hundredsC. HundredsD. One hundred() 29.–Do you often go to school by bus?-No, I go to school my bike every day.A. XXX() 30. - does it take you to get toschool?-Half an hour.A. What timeB. How longC. How farD. What() 31.–How does he usually go to schoolevery day?-He usually to go to school?A. XXXC. XXX() 32. It takes me thirty minutes thereby bus and an hour on foot.A. getB. getsC. gettingD. to get() 33. I’m sorry I haveto my office.It’s too late.A. getB. leave forXXX() 34. It’s aboutwalk from my home to school.A. XXX minutesC. ten minutes’D. ten minute’s() 35. Can you tell me ?A. how old are youB. what’s your nameC. XXXD. how the weather is二、用所给词的正确形式填空。

初中地理易错点分册汇编(附易错题精选与答案)

初中地理易错点分册汇编（附易错题精选与答案）七上易错点01、证明地球是圆球的是月食，不是日食。

02、地球上的东西方向是相对的，因为地球绕自转轴自西向东地转动：地球上的南北方向是绝对的，地球存在南极点和北极点，他们分别是最南点和最北点，但没有最西点、最东点。

,03、“横纬竖经”，纬线表示东西方向，经线表示南北方向。

04、地球公转的意义一般有五带划分、四季变化、太阳直射点移动、昼夜长短变化等；地球自转的意义一般有昼夜更替、时间差异、日月星辰的东升西落。

05、计算比例尺的关键在于实地距离和图上距离的单位要统一成厘米，如1千米=100000厘米。

06、一般既无指向标，又无经纬网时，才按“上北下南，左西右东”的原则定方向。

%07、等高线地形图中，“凸高为谷，凸低为脊”，河流一般发育于山谷中。

08、亚洲面积最大，跨纬度最广，东西距离最广（不等于跨经度最广）。

09、南极洲纬度最高，跨经度最广，平均海拔最高。

10、四大洋中，北冰洋纬度最高，跨经度最广。

,11、太平洋板块中没有大陆，全是海洋；印度洋板块包含了澳大利亚大陆、印度半岛、阿拉伯半岛。

12、南美洲的安第斯山脉是因美洲板块和南极洲板块碰撞挤压而成。

13、雾是水汽凝结物，就像是云在地面上，对人无害；霾是固体漂浮物，比如灰尘，烟等对人有害的。

但两者都会导致能见度下降。

14、一天中，最高气温出现在午后2点左右，最低气温出现在日出前后。

15、判断气候类型的方法：以温定球（看气温最高的月份定南北半球），以温定带（看最低气温定纬度带），以水定型（看降水分布定气候类型）。

16、热带草原气候的降水特征是分干湿两季：热带季风气候的降水特征是分旱雨两季，季节差异更大。

17、世界的语言中，使用人数最多的是汉语，适用范围最广的是英语。

18、发达国家主要分布在欧洲、北美洲和大洋洲；发展中国家主要分布在亚洲、非洲和南美洲。

|19、南南合作是指发展中国家之间的互助合作。

20、有利于聚落形成和发展的条件：地形平坦，交通便利，自然资源丰富，气候温暖湿润，水源充足，土壤肥沃，适于耕作。

初中数学分式易错题汇编附答案解析

【详解】
13．056用科学记数法表示为：0.056= ，故选B.
14．若代数式有意义，则实数的取值范围是（）
A． B．且 C． D．且
【答案】B
【解析】
【分析】
根据二次根式的性质和分式的意义，被开方数大于或等于0，分母不等于0，可以求出x的范围．
【详解】
根据题意得：，
解得：x≥0且x≠1．
11．若，则的值是（）
A． B． C． D．
【答案】B
【解析】
【分析】
直接根据已知用含的式子表示出两数，进而代入化简得出答案．
【详解】
解：∵
∴设，
∴
故选：B
【点睛】
此类化简求值题目，涉及到的字母、利用第三个未知数设出，代入后得到关于的式子进行约分化简即可．将两个字母转化为一个字母是解题的关键．
【解析】
【分析】
根据分式有意义的条件即可求出答案．
【详解】
由题意可知：x-2≠0，
x≠2，
故选：D．
【点睛】
本题考查分式的有意义的条件，解题的关键是熟练运用分式有意义的条件，本题属于基础题型．
9．下列运算中，不正确的是（）
A． B．
C． D．
【答案】A
【解析】
【分析】
根据分式的基本性质分别计算即可求解.
【详解】
解：① ，故①正确；
② ，故②错误；
③ ，故③错误；
④ ，故④错误；
⑤ ，故⑤正确；
∴运算正确的个数有2个，
故选：B．
【点睛】
本题主要考查了负整数指数幂、零指数幂、积的乘方和同底数幂的除法，熟练掌握相关的运算法则是解题的关键．
16．分式的值为，则的取值为（）

中考七年级语法知识-英语单项选择（50题）的易错题汇编附答案及答案

中考七年级语法知识-英语单项选择（50题）的易错题汇编附答案及答案一、选择题1．Last year I had ______ narrow escape from a car crash, and I don’t want to risk my life______ second time.A．a; a B．the; a C．the; the D．a; the2．As he reached _____ back door, Jack saw _____ strange sight.A．the ; / B．a; the C．/; a D．the ; a3．He is in _______ possession of that beautiful garden and the shop is in _______ possession of his brother.A．the; the B．the; /C．/; the D．/ ; /二、选择题4．—What’s on the table?—Can’t you see? There are some ________ of milk.A．packets B．glasses C．bottles D．cartons5．—The air is very fresh in our city. There is less _______ than before.—Yes. The government has taken action to protect the environment.A．wood B．pollution C．noise D．water三、选择题6．— Why do English people talk so often about the weather when starting the talk?—Because the weather is a (an) ________ topic.A．safe B．serious C．awful D．exciting四、选择题7．—My aunt’s 3-year-old daughter can eat a meal with chopsticks.— Really? Most children ________ her age still use spoons.A．of B．in C．on D．for8．China sent up the final satellite of Beidou Navigation Satellite System(北斗卫星导航系统) from Xichang Satellite Center___________ June 23,2020.A．at B．in C．to D．on 9．Armstrong joined the navy in 1949 and served _______ a pilot for three years.A．with B．like C．to D．as五、选择题10．—What do the students think of this book?—It’s really a good book. They all________it.A．look over B．think about C．think highly of D．win the heart of 11．—Have you made a plan to raise money to protect the animals in danger?—Yes. Now we are thinking about how to ________.A．pick it out B．carry it out C．find it out D．put it out12．A big fire ________ in a factory last month. It is important for us to be careful with fire. A．put out B．turned out C．got out D．broke out六、选择题13．Hurry up, or we ________ miss the beginning of the film.A．should B．must C．may D．have to 14．—What is that young lady’s job?—She ________ be a nurse, I’m not sure.A．must B．may C．need D．would 15．We shouldn’t throw any objects from the building. E ven a small object ________ cause serious injuries or death, when dropped from a great height.A．must B．should C．may D．need16．—________ you give me a hand? I can’t put up the poster by myself.—No problem.A．Could B．Should C．Need D．Must七、选择题17．—Did you go travelling during the May Day holiday?—Yes, I did. But you can’t imagine ________ the traffic was!A．What heavy B．what a heavy C．how heavy D．how a heavy 八、选择题18．—___________ can you write in English?—About forty words per minute.A．How far B．How often C．How fast D．How long九、选择题19．When waste from daily life ________, people won’t mix some resources with wet waste. A．separated B．is separated C．separates D．will be separated 20．一The manager has come back from his business trip. He's asking you for the report.一Oh, my god! I haven't finished it yet. But he ________ back at the company tomorrow. A．will expect B．expected C．was expected D．is expected 21．— Soccer first started in England in the 12th century, didn't it?— Yes, but now it ________all over the world.A．plays B．is played C．is playing D．has played 22．—How do you like the poem ? —It’s a bit too long, but anyway, it________well. A．reads B．is read C．is reading D．has read十、选择题23．— Why are the Woods selling their belongings?— They to another city.A．had moved B．have moved C．moved D．are moving 24．— May I speak to Mr. Brown?— I am sorry. He ________ an important meeting in his office now.A．has B．had C．is having D．will have 25．Listen! The birds ________ happily in the tree outside the window.A．sing B．sang C．are singing D．were singing十一、选择题26．The traffic rules say divers mustn’t drive if they are drunk, _______ they will be punished. A．and B．but C．so D．or十二、选择题27．—Summer vacation is coming! Could you tell me ________ ?—Xi’an. I really want to visit Terracotta Army.A．where are you going B．what are you doing C．where you are goingD．what you are doing28．Tomorrow is Earth Day. Let’s discuss ________.A．when shall we give out the leaflets B．what we can do to recycle thingsC．how should we save more energy D．whether can we make our city greener 29．—Excuse me, could you tell me ________?—Better walk there. It’s only about ten minutes’ walk.A．how far Tianle Lake is B．which is the way to Tianle LakeC．how I can get to Tianle Lake D．how can I get to Tianle Lake30．I wouldn’t care about ________, but would be interested in ________.A．who invented paocai ；how does every family make the traditional foodB．who did paocai invent；how every family makes the traditional foodC．who invented paocai；how every family makes the traditional foodD．who did invent paocai；how does every family make the traditional food十三、选择题31．—Dad, it’s difficult for me to clean the whole yard on my own.— Why not ask your brother for help? ________A．Use it or lose it! B．Knowledge is power!C．Practice makes perfect! D．Many hands make light work!32．----I'm tired out.----How can you be manager and accountant at one time? .A．The early bird catches the wormB．Don't put all your eggs in one basketC．Actions speak louder than wordsD．Don't burn the candle at both ends33．—Never give up. If you keep practicing speaking English every day. you’ll make great progress.---Thanks for encouraging me. I know .A．practice makes perfectB．it never rains but it poursC．many hands make light workD．the grass is always greener on the other side34．–I have spent several nights preparing for the coming exam.-It’s bad for you to stay up too late. As the saying goes, "____________".A．You are never too old to learn. B．Actions speak louder than words. C．You can’t burn the candle at both ends.D．You can't put all your eggs in one basket.十四、选择题35．—I thought I’d try to repair the car myself.— __________ ! You know nothing about the car.A．No way B．You can’t be serious C．I couldn’t a gree more D．Don’t change a thing十五、选择题36．－Don’t you think your hair is too long?－Yes. I am going to have it ________ soon.A．cut B．cuts C．cutting D．to cut37．Most of the artists____________ to the party were from South Africa.A．invite B．to invite C．invited D．inviting 38．When I eat a mooncake, I prefer ________ it into small pieces before eating rather than________ it up straight.A．to cut；eat B．cutting；eat C．to cut；to eat D．cutting；eating 39．Our headmaster isn’t in. I can’t find him anywhere. Did you n otice him ______ the office? A．to enter B．entered C．to leave D．leave40．Fans all over the country are talking about ________ this football team has never won any match and ________ to do with it.A．whether; how B．why; how C．whether; what D．why; what 41．Our parents won't allow us _____ in the river alone.A．swimB．to swimC．swimmingD．swam十六、选择题42．—Jim, turn down the music. Our baby is sleeping.—Don’t worry. He__________ for half an hour.A．woke up B．has woken up C．was awake D．has been awake 43．—When did Suning Plaza in Xuzhou open?—It ________ for over three years.A．opened B．has been open C．was opened D．had been open 44．—Is that man George?—It can’t be him. After all he ________ this place for years!A．has left B．has been away from C．was away from D．left45．—Look! The man looks like Mr. Li.—It can’t be him. Because he with his families________Japan since last Thursday and theyhaven’t returned.A．has gone to B．has been to C．have been in D．has been in十七、选择题46．During the quality time at night, the father enjoys watching TV, while the mother together with her three children fond of listening to popular songs.A．is B．are C．was D．were47．It seldom snows in winter here,_______?A．does it B．doesn’t it C．do it D．don’t it十八、选择题48．— Why did your mother get ________ with you just now?—Because I made ________ many mistakes in the exam that she ________ controlled her feelings when she heard it.A．satisfied; so; really B．satisfied; such; nearlyC．angry; so; hardly D．angry; such; mainly49．You will be out of date ________ you keep on studying from time to time.A．unless B．although C．if D．otherwise 50．— I never knew you could make such delicious handmade noodles.—I learned it from an app ________ I stayed at home during the lockdown (封锁).A．since B．before C．when D．until【参考答案】***试卷处理标记，请不要删除一、选择题1．A解析：A【解析】试题分析：考查冠词。

(易错题精选)初中数学有理数易错题汇编附答案解析(1)

（易错题精选）初中数学有理数易错题汇编附答案解析(1)一、选择题1．已知一个数的绝对值等于2，那么这个数与2的和为()A．4 B．0 C．4或—4 D．0或4【答案】D【解析】【分析】先根据绝对值的定义，求出这个数，再与2相加【详解】∵这个数的绝对值为2∴这个数为2或－22+2=4，－2+2=0故选：D【点睛】本题考查求绝对值的逆定理，需要注意，一个数的绝对值为正数a，则这个为±a2．如图，下列判断正确的是（）A．a的绝对值大于b的绝对值B．a的绝对值小于b的绝对值C．a的相反数大于b的相反数D．a的相反数小于b的相反数【答案】C【解析】【分析】根据绝对值的性质，相反数的性质，可得答案．【详解】解：没有原点，无法判断|a|，|b|，有可能|a|＞|b|，|a|＝|b|，|a|＜|b|．由数轴上的点表示的数右边的总比左边的大，得a＜b，由不等式的性质，得﹣a＞﹣b，故C符合题意；故选：C．【点睛】本题考查了数轴、绝对值、相反数，利用不等式的性质是解题关键，又利用了有理数大小的比较．3．数轴上表示数a和数b的两点之间的距离为6，若a的相反数为2，则b为（）A．4 B．4-C．8-D．4或8-【答案】D【解析】【分析】根据相反数的性质求出a 的值，再根据两点距离公式求出b 的值即可．【详解】∵a 的相反数为2∴20a +=解得2a =-∵数轴上表示数a 和数b 的两点之间的距离为6 ∴6a b -=解得4b =或8-故答案为：D ．【点睛】本题考查了数轴上表示的数的问题，掌握相反数的性质、两点距离公式是解题的关键．4．已知a b >，下列结论正确的是（）A ．22a b -<-B ．a b >C ．22a b -<-D ．22a b >【答案】C【解析】【分析】直接利用不等式的性质分别判断得出答案．【详解】A. ∵a>b ，∴a −2>b −2，故此选项错误；B. ∵a>b ，∴|a|与|b|无法确定大小关系，故此选项错误；C.∵a>b ，∴−2a<−2b ，故此选项正确；D. ∵a>b,∴a 2与b 2无法确定大小关系，故此选项错误；故选：C.【点睛】此题考查绝对值，不等式的性质，解题关键在于掌握各性质定义.5．若︱2a ︱＝－2a ，则a 一定是( )A ．正数B ．负数C ．正数或零D ．负数或零【答案】D【解析】试题分析：根据绝对值的意义，一个正数的绝对值是本身，0的绝对值是0，一个负数的绝对值是其相反数，可知a 一定是一个负数或0.故选D6．下列说法错误的是（）A ．2 a 与()2a -相等BC ．D ．a 与a -互为相反数【答案】D【解析】【分析】根据乘方、算术平方根、立方根、绝对值，以及相反数的定义，分别对每个选项进行判断，即可得到答案.【详解】解：A 、()2a -=2 a ，故A 正确；B =B 正确；C 、C 正确；D 、a a -=，故D 说法错误；故选：D.【点睛】本题考查了乘方、算术平方根、立方根、绝对值，以及相反数的定义，解题的关键是熟练掌握所学的定义进行解题.7．﹣3的绝对值是（）A ．﹣3B ．3C ．-13D ．13 【答案】B【解析】【分析】根据负数的绝对值是它的相反数，可得出答案.【详解】根据绝对值的性质得：|-3|=3．故选B ．【点睛】本题考查绝对值的性质，需要掌握非负数的绝对值是它本身，负数的绝对值是它的相反数.8．若关于x 的方程22(2)0x k x k +-+=的两根互为倒数，则k 的值为( )A ．±1B ．1C ．－1D ．0【答案】C【解析】【分析】根据已知和根与系数的关系12c x x a=得出k 2=1，求出k 的值，再根据原方程有两个实数根，即可求出符合题意的k 的值．【详解】解：设1x 、2x 是22(2)0x k x k +-+=的两根，由题意得：121=x x ，由根与系数的关系得：212x x k =，∴k 2=1，解得k =1或−1，∵方程有两个实数根，则222=(2)43440∆--=--+>k k k k ，当k =1时，34430∆=--+=-<，∴k =1不合题意，故舍去，当k =−1时，34450∆=-++=>，符合题意，∴k =−1，故答案为：−1．【点睛】本题考查的是一元二次方程根与系数的关系及相反数的定义，熟知根与系数的关系是解答此题的关键．9．实数a 、b 在数轴上的位置如图所示用下列结论正确的是( )A ．a+b>a>b>a−bB ．a>a+b>b>a−bC ．a−b>a>b>a+bD ．a−b>a>a+b>b【答案】D【解析】【分析】首先根据实数a ，b 在数轴上的位置可以确定a 、b 的取值范围，然后利用有理数的加减运算即可比较数的大小．【详解】解：由数轴上a ，b 两点的位置可知，∵b ＜0，a ＞0，|b|＜|a|，设a=6，b=-2，则a+b=6-2=4，a-b=6+2=8，又∵-2＜4＜6＜8，∴a-b ＞a ＞a+b ＞b ．故选：D ．【点睛】此题主要考查了实数与数轴之间的对应关系，解答此题的关键是根据数轴上a ，b 的位置估算其大小，再取特殊值进行计算即可比较数的大小．10．实数a ，b ，c ，d 在数轴上的对应点的位置如图所示. 若0b d +=，则下列结论中正确的是（）A ．0b c +>B ．1c a >C ．ad bc >D ．a d >【答案】D【解析】【分析】根据数轴上的点表示的数右边的总比左边的大，可得a ＜b ＜0＜c ＜d ，根据有理数的运算，可得答案．【详解】由数轴上的点表示的数右边的总比左边的大，得a ＜b ＜0＜c ＜d ，A 、b+d ＝0，∴b+c ＜0，故A 不符合题意；B 、c a＜0，故B 不符合题意； C 、ad ＜bc ＜0，故C 不符合题意；D 、|a|＞|b|＝|d|，故D 正确；故选D ．【点睛】本题考查了实数与数轴，利用数轴上的点表示的数右边的总比左边的大得出a ＜b ＜0＜c ＜d 是解题关键，又利用了有理数的运算．11．如图，四个有理数在数轴上的对应点M ，P ，N ，Q ，若点M ，N 表示的有理数互为相反数，则图中表示绝对值最小的数的点是（）A ．点MB ．点NC ．点PD ．点Q【解析】试题分析：∵点M，N表示的有理数互为相反数，∴原点的位置大约在O点，∴绝对值最小的数的点是P点，故选C．考点：有理数大小比较．12．如图数轴所示，下列结论正确的是()A．a＞0 B．b＞0 C．b＞a D．a＞b【答案】A【解析】【分析】根据数轴，可判断出a为正，b为负，且a距0点的位置较近，根据这些特点，判定求解【详解】∵a在原点右侧，∴a＞0，A正确；∵b在原点左侧，∴b＜0，B错误；∵a在b的右侧，∴a＞b，C错误；∵b距离0点的位置远，∴a＜b，D错误【点睛】本题是对数轴的考查，需要注意3点：（1）在0点右侧的数为正数，0点左侧的数为负数；（2）数轴上的数，从左到右依次增大；（3）离0点越远，则绝对值越大13．下面说法正确的是()A．1是最小的自然数；B．正分数、0、负分数统称分数C．绝对值最小的数是0；D．任何有理数都有倒数【答案】C【解析】【分析】0是最小的自然数，属于整数，没有倒数，在解题过程中，需要关注【详解】最小的自然是为0，A错误；0是整数，B错误；任何一个数的绝对值都是非负的，故绝对值最小为0，C正确；0无倒数，D错误本题是有理数概念的考查，主要需要注意0的特殊存在14．下列各组数中，互为相反数的组是（）A ．2－B ．2－C ．12-与2D ．【答案】A【解析】【分析】根据相反数的概念及性质逐项分析得出答案即可．【详解】A 、-2=2，符合相反数的定义，故选项正确；B 、-2不互为相反数，故选项错误；C 、12-与2不互为相反数，故选项错误； D 、|-2|=2，2与2不互为相反数，故选项错误．故选：A ．【点睛】此题考查相反数的定义，解题关键在于掌握只有符号不同的两个数互为相反数，在本题中要注意理解求|-2|的相反数就是求2的相反数，不要受绝对值中的符号的影响．15．下列说法中不正确的是（）A ．-3 表示的点到原点的距离是|-3|B ．一个有理数的绝对值一定是正数C ．一个有理数的绝对值一定不是负数D ．互为相反数的两个数的绝对值一定相等【答案】B【解析】【分析】根据绝对值的意义以及相反数的意义逐项进行分析即可得答案.【详解】A 、根据绝对值的意义|-3|表示在数轴上表示-3的点到原点的距离，故A 选项正确，不符合题意；B 、若这个有理数为0，则0的绝对值还是0，故B 选项错误，符合题意；C 、根据绝对值的意义，|a|的绝对值表示在数轴上表示a 的点到原点的距离，故任意有理数的绝对值都为非负数，所以不可能为负数，故C 选项正确，不符合题意；D 、根据相反数的定义可知：只有符号不同的两数互为相反数，可知互为相反数的两数到原点的距离相等，即互为相反数的两个数的绝对值相等，故D 选项正确，不符合题意，【点睛】本题考查了绝对值的意义，绝对值的代数意义为：正数的绝对值等于它本身；负数的绝对值等于它的相反数；0的绝对值还是0；绝对值的几何意义为：|a|表示在数轴上表示a 的这个点到原点的距离，熟练掌握绝对值的意义是解本题的关键．16．已知有理数a 、b 在数轴上的位置如图所示，则下列代数式的值最大的是（）A ．a +bB ．a ﹣bC ．|a +b |D ．|a ﹣b | 【答案】D【解析】【分析】根据数轴确定出a 是负数，b 是正数，并且b 的绝对值大于a 的绝对值，然后对各选项分析判断，再根据有理数的大小比较，正数大于一切负数，然后利用作差法求出两个正数的大小，再选择答案即可．【详解】由图可知，a<0，b>0，且|b|>|a|，∴−a<b ，A. a+b>0，B. a−b<0，C. |a+b|>0，D. |a−b|>0，因为|a−b|>|a+b|=a+b ，所以，代数式的值最大的是|a−b|.故选：D.【点睛】此题考查有理数的大小比较，数轴，解题关键在于利用绝对值的非负性进行解答.17．数轴上A ，B ，C 三点所表示的数分别是a ，b ，c ，且满足||||||c b a b a c ---=-，则A ，B ，C 三点的位置可能是（）A ．B ．C ．D ．【答案】C【解析】【分析】由A 、B 、C 在数轴上的位置判断出a 、b 、c 的大小关系，根据绝对值性质去绝对值符号，判断左右两边是否相等即可.【详解】当a c b ＜＜时，||||c b a b b c a b a c ---=-+-=-，180°-66?38=113?22′′，此选项错误；B 、当a ＜b ＜c 时，||||2c b a b c b a b c a b ---=-+-=+-，44A-mB=，此项错误；C 、当c ＜a ＜b 时，||||c b a b b c a b a c ---=-+-=-，||a c a c -=-，此项正确D 、当c ＜b ＜a 时，||||2c b a b b c a b c a b ---=--+=--+，||a c a c -=-，此选项错误；故选C.【点睛】本题主要考查绝对值性质:正数绝对值等于本身，0的绝对值是0，负数绝对值等于其相反数.18．在﹣6，0，﹣1，4这四个数中，最大的数是（）A ．4B ．﹣6C ．0D ．﹣1 【答案】A【解析】【分析】根据正数大于0，负数小于0，负数绝对值大的其值反而小即可求解．【详解】∵4＞0＞﹣1＞﹣6，∴最大的数是4．故选A ．【点睛】此题主要考查了有理数的大小的比较，解题的关键利用正负数的性质可以解决问题．19．已知整数01234,,,,,L a a a a a 满足下列条件：01021320,1,2,3==-+=-+=-+L a a a a a a a 以此类推，2019a 的值为（） A ．1007-B ．1008-C ．1009-D ．1010-【答案】D【解析】【分析】通过几次的结果，发现并总结规律，根据发现的规律推算出要求的字母表示的数值．【详解】解：00a=，101011a a=-+=-+=-，212121a a=-+=--+=-，323132a a=-+=--+=-，434242a a=-+=--+=-，545253a a=-+=--+=-，656363a a=-+=--+=-，767374a a=-+=--+=-，……由此可以看出，这列数是0，-1，-1，-2，-2，-3，-3，-4，-4，……，（2019+1）÷2=1010，故20191010a=-，故选：D．【点睛】本题考查了绝对值的运算，对于计算规律的发现和总结．20．下列各数中，最大的数是（）A．12-B．14C．0 D．-2【答案】B【解析】【分析】将四个数进行排序，进而确定出最大的数即可．【详解】112024-<-<<，则最大的数是14，故选B．【点睛】此题考查了有理数大小比较，熟练掌握有理数大小比较的方法是解本题的关键．。

2024届高考英语复习易错题专项(代词)练习(附答案)

2024届高考英语复习易错题专项(代词)练习1．（2023年新高考I卷）Nanxiang aside, the best Xiao long bao have a fine skin, allowing them to be lifted out of the steamer basket without tearing or spilling any of ________ (they) contents.2.（湖南省长沙麓山国际实验学校2023-2024学年高三试题）Finding the pe rfect fusion o f tradition and innovation can be like pulling a rabbit out of a hat, but White Rabbit was able to pull off.3.（湘豫名校联考2023-2024学年高三试题）Unlike (it) seemingly simple appearance, making a guqin is extremely demanding.4.（江苏省2023-2024学年高三学情调研试题）We must first of all have confidence in (we).5.（2023年全国高三校考练习）To my disappointment, of the details she told us was exact.6.（2023年全国高三校考练习）Within industries, companies are always trying to develop products that are one step better than of other companies.7.（2023年全国高三校考练习）Building a new school is one thing, while keeping it running smoothly is quite.8.（2023年全国高三校考练习）Sometimes,we take for granted that everything has to be perfect for us and we expect high q uality products and service.9.（2023年全国高三校考练习）The old man has three sons, but none of (they) is a doctor.10．（2023年全国高三校考练习）—How about the price of these refrigerators?—They’re equal in price to, if not cheaper than, the at the other stores.11.（2023年全国高三校考练习）This school is one of the top schools in our city, equipped with modern teaching equipment.12．（2023年全国高三校考练习）He got a new haircut and got (he) up in a suit, then headed for the hall.13．（2023年全国高三校考练习）Smith has two strategies, of which seems to have worked very well.14.（2023年全国高三校考练习）You ought to behave in public, or you may annoy the people around you.15.（2023年全国高三校考练习）The man distinguished (he) by his wisdom.参考答案1．（2023年新高考I卷）Nanxiang aside, the best Xiao long bao have a fine skin, allowing them to be lifted out of the steamer basket without tearing or spilling any of ________ (they) contents.【答案】their【答案详解】考查代词。

七年级英语下期中复习易错题汇编(带答案)

一，用所给词的适当形式填空1.Is the Eiffel tower the tallest building in (French)2.At Spring Festival , each of the children in thefamilies (get) red packets.3.Peter often spends too much time (play) computer games at weekends.4.Mother tells Mary (make)the bed by herself.5.Lily often makes her brother (do) homework for her.6.Does it take you twenty minutes (go) to work by car every day?7.We hope (go) and watch the football game in the playground.8.Let you and me (be) good friends.9.I don’t have much time (play) table tennis.10.There are millions of people (live) in poor areas in China.11.Thank you for (show) me the way.12.Don’t be afraid (speak) in front of the people.13.We need some volunteers (do) some cleaning for old people.14.Why not try (fix) the bicycle by yourself?15.How about (help) your brother (check) his computer.16.My mother is a teacher, and my mother is a (cook).17.Miss Kong teaches (we) English.18.The question is easy (answer).19. Try your best (finish) this work.20.There are (many) apples (eat) and thereis (many) juice (drink).21.My sister is afraid （介词）the snake（蛇）,She isafraid (see) them.22.—What you (be) when you grow up?—I’m going to bea teacher.23.We are happy (have )PE lesson .We havefun (play) all kinds of ball games.24.You can play computer games after (finish) your homework.二、单项选择1.—Can I tell Sam this news? —No I don’t want else to know it.A. anyoneB.anythingC.someoneD.no one2. his mother, John the balcony in their house.A.Like, is likeB.Likes, likesC.Like, likesD.Likes, is like3.There is a lake in our school.We can see the beautiful trees around the lake our classroom windows.A.ofB.inC.atD.from4.The shop near my house from 7:00 to 19:00.A.is openB.is opendC.is openingD.open5.—Would you like some milk?—A．Yes, I’d like to. B.Yes, thanks. C.Yes, please D.Thank you.6.—is it from your home to your school? —About half a hour by bus.A.How longB.How farC.How awayD.How much7. my classroom there is a map of the world.A. In front ofB.BehindC.BeforeD.At the back of8.The room is for us. There are in it.A.big enough, chairs enoughB.enough big, enough chairsC.big enough, enough chairsD.enough big, chairs enough9.The houses in this area each five rooms. A.thereare B.with C.have D.has10.What kind of home do youlive ? A.in B.on C./ D.with11.I wish you tomorrow. A.can come B.will come C.to come D.A and B12.About two students are having the meeting in the hall now.A.hundredsB.hundreds ofC.hundredD.hundred of。

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7A 错题汇编01一、单项选择：1．The librarian helped find some books.A. theyB. theirC. theirsD. them2．The naughty boy made laugh.A. weB. ourC. usD. ours3．I live 2,200 metres the school.A. awayB. far awayC. far away fromD. away from4．Mary is a good student. She her lessons.A. all likesB. is likes allC. is all likesD. likes all5．She is not kind to others, so she has friends.A. fewB. a fewC. littleD. a little6．Each of us has life goals, which will guide us to a bridge future. Without life goals, we may waste our lifetime.A. fewB. a fewC. littleD. a little7．It’s time supper.A. atB. inC. onD. for8．Mr. Brown comes America.A. atB. fromC. inD. to9．What’s the time your watch?A. onB. withC. byD. in10．What’s the for each child?A. placeB. priceC. locationD. district11．We are looking forward you.A. to seeB. seeingC. to seeingD. of seeing12．? I’ve got a headache and a cough.A. What’s your troubleB.What’s wrong with itC. Can I help youD. How are you13．--- is your sister ?--- The one behind the tree.A. Whose girlB. Who’s that girlC. Which girlD. Where’s the girl 14．will your father be back?A. How longB. how oftenC. How soonD. How wide15．You can learn more about the plan New York Radio.A. onB. in C .at D. to16．There a meeting this evening.A. will beB. will haveC. are going to beD. is going to have17．Do you know the answer that question?A. forB. ofC. toD. in18．He was born a summer morning.A. inB. onC. atD. to19．We’re looking forward to a match with Class 2.A. havingB. haveC. hasD. play20．Today is January 1st. Let’s it together.A. to celebrateB. celebratesC. celebratingD. celebrate21．Can you wait for me after school.A. some timeB. sometimeC. sometimesD. some times22．How do you go back every day? I .A. walk to homeB. walk at homeC. walk homeD. walk for home23．Must we finish our homework today?No, you .A. mustn’tB.needn’tC.can’tD. may not24．My favorite food noodles and dumplingsA. isB. areC. doD. does25．I spend 20 yuan computer games every month.A. to buyB. on buyC. buyingD. in buy26．Don’t too much time .A. spend; to shopB. spends; to shoppingC. spend; in shoppingD. spend; on shop 27．Mother likes watching TV before to bed.A. goB. goes C . to go D. going28．People can buy different of food in this shop?A. kindB. kindsC. a kindD. an kind29．Tom Tim are fond of watching TV.A. not only…but also…B.both…and…C.either…or…D.neither…nor…30．nice weather it is! Let’s play football.A. WhatB. HowC. What aD. How a31．The girl really doesn’t know next.A. what to do itB. how to do itC. how to doD. what she can do it32. The girls happy today.A. isn’tB.aren’tC.don’tD.doesn’t(出自课课练)33. --- Are you my new classmates?--- Yes, .A. you areB. we areC.I amD. I’m34. ---your name Millie?---A. Are; Yes, I amB. Is; Yes, it isC. Is; Yes, I amD. Are; Yes, it is35. --- What in the bottle?--- There some juice in it.A. is; isB. is; areC. are; isD. are; are36. --- your cousin Andy good at football?--- Yes. He often plays it.A. IsB. AreC. DoesD. Do36．37．Amy usually from school, but today she goes home by bile.A. walk homeB. walk to homeC. walks homeD. walks to home 38．Mary needs help. Let’s go and help .A. our; sheB. our; herC. us; herD. their; her39. --- How about shopping this evening?--- Good idea!A. goB. to goC. goingD. goes40．We want to know bag this is.A. whatB. whoC. who’sD. whose41．All the teachers enjoy themselves on 8 March every year.A. womenB. menC. womanD. man42. ---your raincoat. It’s raining outside.--- Mum, I don’t like the raincoat.A. Putting on; wearingB. Wearing; putting onC. Wear; putting onD. Put on; wearing43. There homework to do at the weekend.A. are manyB. are lots ofC. are someD. is lots of44. --- It’s late now, Millie. It’s time to go to bed.--- But I still have homework to do.A. too much; too muchB. much too; much tooC. too much; much tooD. much too; too much45. --- Amy, you look nice in this dress.--- .A. You tooB. You’re welcomeC. Thank youD. Don’t say that46. --- Wow, the scarf feels so soft.--- It’s made silk and made Suzhou.A. of; fromB. from; ofC. of; inD. from, in47．Michael is a student and he is in .A. class 8, grade 7B. grade 7, class 8C. Class 8, Grade 7D. Grade 7, Class 8 48．You like Maths very much. What about ?A. hisB. heC. herD. she试卷49．There is U and R in the word OUR.A. a, aB. an, anC. an, aD. a, an50．--- ? --- He is kind and helpful.A. What does he like?B. What is he like?C. What does he look?D. What does he look like?51．Lee born Shanghai October 3rd. 1990.A. Is, in, inB. Is, in, onC. Was, in, onD. Was, in, in52．--- What in the pencil-box?--- a rubber and two pens.A. is, There’reB. are, There’reC. are, There’reD. is, There’s53．--- Is Lucy from ? --- No, she is an .A. America; EnglandB. England, AmericanC. English, America C. American, England54．Let’s go to school, ?A. will youB. do youC. are youD. shall we55．--- Do you listen to music your free time ?--- No, I don’t. I often read story books.A. on, a lot ofB. on, manyC. on, lots ofD. in, much56．--- Tom in the English Club?--- Yes, but he go there very much.A. Does, doesn’tB. Does, isn’tC. Is, doesD. Is, doesn’t57．--- he from England?--- No, he .A. Is, come, isn’tB. Does, come, isn’tC. Is, come, doesn’tD. Does, come, doesn’t58．We can usually a rainbow(彩虹) in the sky after rain in summer.A. look atB. readC. seeD. watch59．--- Tom, can you this word in Chinese?--- Yes, I can ______ a little Chinese now.A. speak, sayB. say, speakC. tell, speakD. talk, say60．I live 2,200 metres the school.A. awayB. far awayC. far away fromD. away from61．Mary is a good student. She her lessons.A. all likesB. is likes allC. is all likesD. likes all62．--- did the important meeting ?--- For about two hours.A. When, beginB. How long, beginC. When, lastD. How long, last 63．This kind of computer too much, I can’t afford one.A. takesB. spendsC. paysD. costs64．Plan your time carefully and make sure you have some time what you like every day.A. doB. to doC. doingD. done65．--- I went to have the driving test this morning, but I didn’t pass it.--- .A. Luck decides everythingB. Better luck next timeC. But you can drive wellD. You are always unlucky66．Our school library at 9 in the morning and at 5 in the afternoon.A. is open, is closedB. opens, closesC. is opened, is closedD. is opening, is closing67．She spends her free time in the Club.A. reading, ReadingB. to read, ReadingC. to read, ReadD. reading, Read68．Jim sits between and . We are good friends.A. her, meB. she, IC. I, sheD. me, her69．do the boys often do in the evening? They do their homework in the classroom.A. WhoB. WhatC. HowD. Where70．The students of Class 1 at school today.A. all areB. are allC. are bothD. both are71．--- I get 100 points for English. --- .A. Good luckB. Really? congratulationsC. It’s OKD. Not at all72. --- There are lots of CDs on the desk. would you like to listen to?--- Jay Chow’s. He is my favo rite hero.A. WhereB. WhoC. WhichD. When73. fun we have a big dinner!A. How, havingB. What , havingC. How, to haveD. What, to have74. There isn’t tea in the cup. Would you like water?A. some, anyB. any, someC. some, someD. any, any75. She always has an apple supper.A. withB. forC. ofD. to76. --- kilos of rice do you want?---Five kilos, please.A. How manyB. How muchC. How aboutD. How old77. I don’t like cakes sweets .A. and, allB. and, very muchC. or, tooD. or, at all78. You need to do morning every day. It’s good to have lots of .A. exercises, exerciseB. exercise, exerciseC. exercises, exercisesD. exercise, exercises79. the apple , you should wash it first.A. To eatB. EatC. EatingD. For eat80. --- TV does he watch every day?---Three hours of TV.A. How longB. How oftenC. How manyD. How much81. Don’t spend too much time.A. to shopB. on shopC. in shoppingD. shop82. Is there in today’s newspaper?A. something importantB. important somethingC. anything important C. important anything83. The hair clips cost .I don’t want to buy them.A. muchB. littleC. dearD. cheap84. There’s going to in tomorrow’s newspapers.A. have something newB. have new somethingC. be something newD. be new something85. He can two hours us our English.A. spend, on, withB. cost, to help, onC. spend, helping, withD. take, to help, with86. ---Do you know the girl in red is?----I’ve no idea. Maybe a teacher.A. whenB. whoC. whereD. what87. There going to two football matches this evening.A. is, haveB. is, beC. are, haveD. are, be88. Dad, my jeans are old! I want to buy a new .A. jeansB. oneC. itD. pair89. The talk show on TV is very famous. It often makes people .A. laughB. laughingC. to laughD. laughs90. ---Where the twins ?--- England.A. does, fromB. are, come fromC. do, come formD. is, from91. The teachers in our school work hard, so they go home very .A. lateB. laterC. latelyD. latest92. everyone to go shopping?A. Does, wantsB. Does, wantC. Do, wantD. Do, wants93. Lily and Lucy love very much. But this weekend they like .A. to dance, singingB. dancing, to singC. dancing, singingD. to dance, to sing94. your brother good at Chinese?A. Is , to learnB. Does, learningC. Is ; learningD. Does, to learn95. If you have a dream, you should try hard to make it .A. coming trueB. comes trueC. come trueD. to come true96. ---Who teaches English this term?--- Miss Li .A. our , doesB. us, doesC. us, isD. our, is97. The park is eight hours a day. It at 9:00 in the morning.A. open, openB. opens, opensC. open, opensD. opens, open98. --- of the teachers is Mr. Green?--- The one in blue trousers.A. WhoB. WhoseC. WhatD. Which99. Most students are not happy, because they have homework to do.A. too muchB. too manyC. much tooD. many too 100. It’s Saturday morning, but his mother early.A. wakes up himB. wake up herC. wakes him upD. wake her up 101. --- does Kitty dance every day?--- Two hours.A. How oftenB. How longC. How manyD. How soon 102. I’m sorry. I don’t know make a model plane.A. how can IB. how do IC. I how toD. how to 103. ---Do you do morning every day?---Yes, I take some for half an hour every morning.A. exercise, exerciseB. exercises, exerciseC. exercises, exercisesD. exercise, exercises104. Thank you for me clean the classroom.A. help, withB. help, /C. helping, withD. helping, / 105. Children in China usually start to go to school the age of eight.A. inB. atC. onD. to106. Trainers are for a long walk.A. matchingB. matchC. fittingD. fit107. This book has many parts, tour, food and local people.A. includedB. includesC. includingD. include 108. We our homework before lunchtime.A. needn’t to finishB. don’t need finishC. needn’t finishD. don’t need finishing109. There some news about the poor students the newspaper.A. is, onB. is, inC. are, onD. are, in110. I think the orange juice .A. drinks wellB. tastes wellC. drinks goodD. tastes good111. --- TV do you watch every day? ---Two hours.A. How longB. How muchC. How oftenD. How many hours112. How many do you want?A. glass of apple juiceB. glass of apple juicesC. glasses of apple juiceD. glasses of apple juices113. Jack in the park every morning to keep fit.A. takes exercisesB. does exercisesC. exercisesD. do exercise114. The new flat Mr. Black a lot of money.A. spendsB. paysC. costsD. takes115. The little boy is not to look after himself.A. old enoughB. enough oldC. young enoughD. enough young116.---Is there bread in the fridge?---No. But there are cakes in it. Would you like ?A. any, any, someB. any, some, someC. some ,some, anyD. some, any, some 117. there any bread and in the shop?A. Is, fruitsB. Are, fruitC. Is, fruitD. Are, fruits118. --- is the coat?---It’s 499 yuan.---Oh, the price is too .A. How many, highB. How many, expensiveC. How much, highD. How much, expensive119.This pair of shoes you very well.A. fitsB. fitC. matchesD. match120.Thanksgiving Day is important day in USA.A. a, theB. an, theC. an,/D. a,/121.--- would you like?--- The red one.A. What colorB. WhatC. WhichD. Which color122. get together on Mid-Autumn Day in china.A. Most family membersB. Most of family memberC Most of. members D. Most of the families123.Remember to an umbrella with you when you go out.A. takeB. bringC. holdD. haveKey1-10 D C D D A , D D B C C 11-20 C A B C A ,A C B A D 21-30 A C B C A , C D B B A 31-40 B B B B A , A C B C D 41-50 A D D D C ,C C C D B 51-60 C D B D D , D D C B C 61-70 D D D B B , B A A B B 71-80 B C B B B , A D A A D 81-90 C C A C C, D D D A C 91-100 A B B C C, B C D A C 101-110 B D B D B ,D C C B D 111-120 B C C C A , B C C A B 121-130 D A A。