重难点突破练习(1)
北师大版小学数学四年级上册重难点突破试题全套
北师大版小学数学四年级上册重难点突破卷1动手操作能力一、我会画。
(每题6分,共36分)1.过点A分别画出下面直线的垂线。
2.过直线外一点O,分别画出直线AB的平行线。
3.在方格中分别画一组平行线和一组互相垂直的直线。
4.从下面射线的一端A点开始,截取一条3厘米长的线段AB。
再以点A为顶点画一个65°的角。
5.用量角器分别画出60°和125°的角。
6.找规律,画一画。
二、我会连。
(每题6分,共12分)1.观察算式的特点,连一连。
2.每个盒子里可能摸出什么球?(连一连)三、我会按要求解决。
(每题6分,共24分)1.用三角尺比一比,下面图形中哪两条边是互相垂直的?请画上直角符号。
2.先估一估下面各角的度数,再量一量。
3.从下图中各找出两组互相平行的线段,并用不同的颜色描出来。
4.涂色表示出气温。
四、走进生活,解决问题。
(第1题8分,第2、3题每题10分,共28分)1.按要求作图。
(1)画一条从小木屋到蘑菇房的最近的路。
(2)画一条从蘑菇房到小河的最近的路。
2.四个小朋友做“抢椅子”的游戏,他们的位置如下。
谁最有可能先坐在椅子上?你能说出理由吗?3.按要求完成各题。
(1)公园的西面600米的地方有一个邮局,请你用△标出它的位置。
(2)邮局的北面400米的地方有一所学校,请你用☆标出学校的位置。
答案一、1.2.3.略4.5.6.二、1.2.三、1.2.12045603.略4.四、1.2.小龙,因为小龙离椅子最近。
3.重难点突破卷2数对、可能性的判断与分析一、我会填。
(第2题2分,第4题4分,其余每空2分,共16分)1.数对(3,7)表示这个物体在第3列,第7行,那么数对(5,6)表示这个物体在第()行,第()列。
2.刘强坐在教室的第5列第2行,用数对(5,2)表示;李方坐在刘强的正前面,李方的位置用数对(,)表示。
3.鲤鱼()在天上飞;人类的生存()离不开水;买彩票()中大奖。
2021年河南中考英语总复习重难点突破练习:阅读理解(有答案) (1)
2021河南中考英语总复习重难点突破练习:阅读理解1.Once there was a club that only smart people could join. Many people wanted to join it so that they would be able to spend more time with other smart people.One night, the club's members were having a dinner party in a restaurant. They talked and enjoyed their food. One of them thought that his salad tasted a little boring, so he asked for a salt shaker(调料瓶)and added some salt. However, it turned out to be sugar. The group found that the salt on the table was in the sugar shaker while the sugar was in the salt shaker.The club members told the waiter about the problem. But there were no other bottles. How could the waiter solve this problem? After a long discussion, the group suggested some ways to make it right.But the waiter simply looked at the shakers and said, "It's easy." He took the labels(标签)off both shakers and exchanged(互换)them. The room quickly became silent.Sometimes we make problems more difficult to solve than they should be.It's good to take a step back and see if there is a simpler way first.(1)Many people hoped to join the club because ________.A.they thought they were not smart enoughB.they could get free mealsC.they would be around smart peopleD.they could spend more time eating(2)What problem did the group run into?A.Their salad tasted a little boring.B.They had nothing to eat but the salad.C.There was no salt or sugar shaker on the table.D.Sugar and salt were put in the wrong shakers.(3)How might the group describe the waiter at last?A.He was lazy.B.He was clever.C.He was shy.D.He was friendly.(4)What does the story teach us about the problems we face?A.Ask others for advice.B.Think out of the box.C.Leave them for the smart.D.Solve them on our own.2.Airports(机场)can be interesting places to work. There are many different kinds of jobs. But do you know how to get such a job?Find a Job You Would EnjoyIn the beginning, you need to search for necessary information like available jobs in the air travel industry(行业). Then you can look through the job that interests you most. Next you have to find out what training, qualifications(证书), education, or skills it needs.Make Your Resume(简历)A good resume should include your full personal information such as name, address, phone number, e-mail and work experience. It can help others know you clearly and quickly. They will use your resume to see if you are able to do the job well.Prepare for Your Interview(面试)Once you get a call for the interview, you have to prepare for it. On the one hand, you must make sure not to be late for it. You can set an alarm to remind yourself. On the other hand, you should try to give a good performance. You can practice yourself by thinking about what questions will be asked and how you will answer them.(1)What should you do first if you want to find a job in airports?A.Look through the interesting. jobs.B.Search for the information about available jobs.C.Find out what the job needs.D.Ask people in the air travel industry for help.(2)What does a good resume NOT need according to the material? and address.B.Phone number.C.Work experience.D.Personal hobbies.(3)What do we know from the material?A.The airport only offers a few jobs.B.People should find relaxing jobs.C.A good resume can help others know your ability(能力).D.It's natural for people to be nervous before an interview.(4)What will the writer most probably talk about next?A.Other ways of self-practice.B.An example of a good resume.C.People's ideal(理想的)jobs.munication skills on the phone.3.A man owed(欠)a large amount of money to a loan shark(放高利贷者). The loan shark happened to love the man's daughter very much.He told the man that there was a chance to clear the debt(债务).He told the man and his daughter that he would place two pebbles(鹅卵石)into a bag—one was white and one was black. The daughter would then reach into the bag and pick out a pebble. If it was black, he would clear the debt, but the man would let him marry the girl. If it was white, he would also clear the debt, but the daughter wouldn't have to marry him.He then bent over and picked up two small stones from a path full of pebbles. The daughter happened to see that the two pebbles he picked up were both black!He then asked the daughter to pick a pebble from the bag. She did so, but before looking at it, she dropped it among the other pebbles on the path.She said to the loan shark, "Oh, how stupid of me. Never mind, if you look into the bag for the one that is left, you will be able to tell which pebble I picked."The pebble left in the bag, of course was black. The loan shark had to recognize the pebble the daughter dropped was white and clear her father's debt.(1)What color were the two pebbles that the loan shark put into the bag?A.Both white.B.Both black.C.White and black.D.White and red.(2)The underlined word "recognize" in the passage means "________" in Chinese.A.承认B.争辩C.解释D.挑选(3)What is the story's result?A.The daughter married the loan shark.B.The father fought with the loan shark.C.The father had to pay for the debt.D.The daughter wouldn't marry the loan shark.4.(1)The museum is closed on ________.A.MondayB.TuesdayC.FridayD.Sunday(2)What can we NOT learn from the information above?A.Where you can find the museum.B.How many museum guides the museum needs.C.What people can get as volunteers there.D.How to get more information about the museum.(3)If someone wants to know more information about volunteering, he can ________.A.send a letterB.make a call to Miss BrownC.ask the museum's managerD.visit its website5.Susan's Plan(1)Susan ________ from Monday to Friday.A.goes to schoolB.does her homeworkC.watches TVD.goes shopping(2)Susan would like to ________ on Saturday morning.A.stayathomeB.do her homeworkC.go shoppingD.go swimming(3)Susan can see some animals ________.A.on MondayB.on FridayC.on SaturdayD.on Sunday(4)Susan does her homework ________.A.on Saturday eveningB.on Saturday afternoonC.on Tuesday afternoonD.on Sunday afternoon(5)On Monday evening Susan ________.A.has a dance lessonB.reads booksC.watches an English moviesD.watches TV6.(1)Lucy is a good teacher and she wants to find a job. She can call ________ for the job.A.TinaB.JohnC.JaneD.Mr. Smith(2)You can be in the Chinese Character Club for ________ to learn Chinese characters from Monday To Friday.A.2.5 hoursB.3.5 hoursC.4 hoursD.5 hours(3)If you look for a job as a musician, you can________.A.go to Room 212 in School's P. E. BuildingB.send an e-mail to music@163. com.C.call Mr. Smith at 368-5778D.call Jane(4)Who can teach you to play soccer?A.Tina.B.John.C.Jane.D.Mr. Smith.(5)If you want to be a musician, you must ________.A.write Chinese characters wellB.speak English wellC.play an instrumentD.like children very muchMy name is Steve. On weekdays I get up at 6:30. I take a shower, brush my teeth and get dressed. I don't have breakfast at home. I eat a sandwich(三明治)and drink some milk on the bus to school. At about 7:45 I get to school and the first lesson starts at 8:00. I usually have 6 lessons a day. At 11:30, I have lunch in the dining hall. After lunch I do some school activities. I go to the music club or play sports with my friends. School finishes at four o'clock in the afternoon. I usually get home at about 4:30. My first thing to do after school is to do my homework. After that I have some free time. I often watch TV, play on the computer, play with my friends, help my mother with dinner or go shopping with her. At about half past six we have dinner. After dinner I usually do some reading. Reading is my favorite hobby(业余爱好). After about one and a half hours' reading, I wash my face and brush my teeth. Then I go To bed at 9:30.(1)When does Steve get up on weekdays?A.At 5:30B.At 6:00C.At 6:30D.At 7:00(2)How does Steve go to school?A.By bike.B.On foot.C.By subway.D.By bus.(3)What does Steve do after lunch in the school?① He plays sports.② He cleans the classroom.③ He goes to the music club.④ He draws pictures.A.①②B.①③C.②④D.③④(4)What's Steve's first thing to do after school?A.Help his mom with dinner.B.Do his homework.C.Have dinner.D.Watch TV.(5)How long does Steve read before he goes to bed?A.For 30 minutes.B.For all hour.C.For 90 minutes.D.For two hours.8.Many young people can't care for themselves well after leaving home. They can't even wash a pair of socks. I don't want to be a person like that. I want to be more independent.When I was only seven years old, I liked cooking with my mother in the kitchen. I learned how to cook from my mother there, and she was really interested in teaching me. Before my mother got married, she didn't know how to cook, because my grandmother didn't allow(允许)her to cook. My mother did not start cooking until she was 25 years old. At the beginning, it was difficult for her. She had to take cooking lessons. She decided to teach me when I was young, because she didn't want me to have the same experience as she did.And now I can do many chores by myself. I can wash my own clothes, and sometimes I do that for my parents and my brother. When my parents get out, I can cook meals for myself and my brother.(1)The writer's mother learned cooking by ________ at the beginning.A.learning from her motherB.reading booksC.taking cooking lessonsD.learning from her daughter(2)The underlined word "married" in Paragraph 2 means ________.A.出生B.毕业C.结婚D.退休(3)The writer mainly wants to tell us ________.A.when his mother learned to cookB.his mother taught him how to cookC.the earlier kids learn to be independent, the better it is for their futureD.he could cook and do many chores by himself9.Tammy's body was shaking! Today was her first trip to the dentist. She didn't know what to expect. What would happen? Would it hurt? Would she shout?Mom said it wasn't scary at all, but Tammy didn't know. How bad would it be? The dentist would clean her teeth. Then he would take pictures of her teeth to see if they were rotten(腐烂的).That didn't sound too bad. She cleaned her teeth at home already. She liked to smile(笑). She wanted clean teeth and didn't want rotten teeth. Pictures and cleaning sounded OK with her.At the office, many people were waiting. There was a fish tank(鱼缸)to look at and magazines to read. She chose a magazine and found it interesting. She didn't have to wait long, though. Soon it was her turn.The dentist was a kind, old man. He smiled and Tammy sat in a special chair. There were lots of lights and tools(工具). It didn't make her comfortable when she opened her mouth. He looked really closely. He cleaned her teeth carefully and then took pictures of her teeth. Then she was done.That was it? That wasn't that scary. The dentist told her that she needed to come back again in six months. "Sure. I will. I can come by myself!" Tammy smiled.(1)From the three questions in Paragraph 1, we can know Tammy was________.A.boredB.worriedC.surprisedD.excited(2)What did Tammy do when she waited at the office?A.She watched fish.B.She read a magazine.C.She talked with her mom.D.She played with other kids.(3)As for the next meeting with the dentist, Tammy planned to come________.A.aloneB.with her momC.the next weekD.the next month(4)What's the best title for the passage?A.A long waitB.A busy dentistC.Tammy's questionsD.First trip to the dentist10.Riding a bicycle has become very popular these days.My school is far from my house, so I went there by bus for years. I sometimes got there late. This March I asked my father to get me a bicycle so that (以便)I might get to school on time. And he bought me one some days later.Then the problem was how to ride the bicycle. One of my friends lives next door. He helped me learn how to ride. He took me to a school playground and demonstrated(示范)how to ride to me. When it was my turn to ride, he ran with me. He did that to make sure he would be there when I was falling off. I learned things very quickly and could ride a bicycle without anyone's help after a few days.What fun it is to ride a bicycle! I now go to school on my bicycle. I think a bicycle is the cheapest and quickest means of transport(交通工具)for a student.I make use of my bicycle if a football game is waiting for me in the park. I visit the homes of my friends who live too far away by bicycle. I can also be very helpful to my mother and get vegetables and fruit for the house.What fun it is to fly like a bird on my bicycle!(1)Who bought a bicycle for the writer?A.His father.B.His mother.C.His friend.D.His teacher.(2)The writer learned how to ride a bicycle ________.A.by himselfB.in a few weeks' timeC.with his father's helpD.on a school playground(3)What does the writer think of riding a bicycle?① It's cheap. ② It's hard. ③ It's quick. ④ It's fun.A.①②③B.①②④C.①③④D.②③④参考答案1.【答案】CDBB【解答】(1)C 细节理解题。
人教版小学数学四年级下册重难点突破试题全套
人教版小学数学四年级下册重难点突破试题全套重难点突破卷1一、数学技能1.0.07的计数单位是百分之一,再加上100个这样的计数单位是1.2.0.354.3.8.原数是0.08,去掉小数点后为8.4.0.99,它与1相差0.01.5.“7”在整数位上,表示7,“6”在百分位上,表示六十分之六。
6.12.25米。
7.(1)1.6 (2)0.68,0.56.二、数学知识1.×,6.800是三位小数,不能说是一位小数。
2.√,3.203精确到百分位约是3.2.3.×,小数加减法要把小数点对齐,而不是末位数字。
三、选择题1.C,整数部分是0的小数一定比1小。
2.C,共有8个一位小数。
3.A,正确的差是14.42.四、计算题1.10.3÷100=0.1032÷1000=0.0021.8×10÷100=0.18360÷100×10=36015-0.3=14.76-0.5=5.53.9+12.1=162.13+4=6.132. 64.7 36.8101.5 25 4.7320.27 37.9 2.6340.53 10.1 3.826.283.45.36+(83.4-15.07)=113.6967.39-(12.67+17.39)=37.334.5+3.8+15.5=23.842×101=4242五、应用题1.竹竿的长度为0.5+0.86=1.36米,池中水深为4-1.36=2.64米。
2.(1)需要题目给出的价格才能计算。
2)例如:XXX每天花费1.5元买牛奶,他一个月喝了多少钱的牛奶?答案:45元。
一、我会填。
(每题4分,共24分)1.XXX家有兔和鸭若干只,从上面数有10个头,从下面数有28只脚,兔有(4)只,鸭有(6)只。
2.2元和5元的人民币共9张,合计33元,2元的有(6)张,5元的有(3)张。
1.XXX家有兔和鸭若干只,从上面数有10个头,从下面数有28只脚。
2023年中考物理重难点突破专题一:光学作图
2023年中考物理重难点突破
10.(2021重庆)在凸透镜
光路图
说明
平行于凸透镜主光轴的光线,经过凸透 镜后过另一侧的焦点。
凹透镜
从凸透镜焦点发出的光线,经过凸透镜 后平行于主光轴。 经过凸透镜光心的光线,传播方法不改 变。 平行于凹透镜主光轴的光线,经过凹透 镜的反向延长线交于同侧焦点。
射向凹透镜另一侧焦点的光线,经过凹 凸镜后,平行于主光轴。
专题一 光学作图
2023年中考物理重难点突破
一、光的反射作图 作图依据:光的反射定律 【例题1】(2022黔西南)阳光与水平面成60°角
射向地面,用平面镜使阳光竖直射入井底,在图中 画出平面镜的位置,并标明反射角的度数。
2023年中考物理重难点突破
【分析】因为太阳光竖直射入深井内,所以反射光线竖直向下,画 出法线,过入射点画出法线的垂线,即平面镜的位置;因入射光线 与水平面成60°,而反射光线是竖直向下的,所以入射光线与反射 光线的夹角为60°+90°=150°,则入射角、反射角为75°。如 图所示:
轴的光线经凸透镜折射后的光线。
2023年中考物理重难点突破
【分析】入射光线平行于凸透镜的主光轴,根据凸 透镜的三条特殊光线可知:平行于凸透镜主光轴的 光线,经过凸透镜后过另一侧的焦点。所以将入射 点与另一侧焦点相连并延长即可,如下图所示:
2023年中考物理重难点突破
【突破】透镜的三条特殊光线
【突破】对于光的反射作图,运用数学上做等角的方法 即可,但必须以法线为始边。注意箭头的方向:入射时 指向反射面;反射时,离开反射面;法线做成虚线,且 需垂直于反射面,过入射点。确定反射角的读数时,依 据反射角等于入射角;法线为反射光线与入射光线组成 的角的角平分线。
专题突破高二化学重难点专题突破(人教版2019选择性必修1)(1)
[提升2]工业生产中产生的SO2废气常用NaOH吸收。25℃时,用0.1 mol·L-1NaOH 溶
液滴定20 mL 0.1 mol·L-1H2SO3,溶液pH的滴定曲线如图。下列说法错误的是(
A.若a点时c(H2SO3)=c(HSO3-),则Ka1(H2SO3)=10-
B.滴定时,可用甲基橙作为b点的终点判断指示剂
选择性必修1(人教版2019)
2023-2024学年
第三章
水溶液中的离子反应与平衡
水溶液中的三类离子反应图像
突破点1:滴定曲线分析
酸碱滴定曲线是以酸碱中和滴定为载体,通过酸碱滴定过程的分析,综合考查指示
剂的选择、水的电离程度变化、溶液导电性变化、溶液温度变化、电离常数计算、
离子浓度大小比较、离子浓度守恒关系等。
选D。
(
)
【解析】若a点pH=4,(H+)=10-4mol·L-1,溶液呈酸性,根据方程式知c(HClO)=c(Cl-)c(ClO-),c(Cl-)= mc(ClO-),则c(HClO)=(m-1)c(ClO-),
Ka(HClO)=
cH
c ClO
c HClO
c H c ClO
= m 1
c ClO
10 4
m 1
,A错误;若x=100,氯水恰好与
NaOH溶液完全反应生成NaCl、NaClO,NaClO水解生成次氯酸,溶液呈碱性,但次氯酸具有
漂白性,不能用pH试纸测pH,应选pH计测量,B错误;b~c段,随NaOH溶液的滴入,溶液的pH
不断增大,溶液中c(H+)减小,温度不变则Ka(HClO)=
3 )+c(OH ),c 点 pH=7.19,
一年级下册《总复习》重难点突破(第1课时)
一年级下册《总复习》重难点突破(第1课时)1.全面回顾、梳理、总结所学知识,初步了解总复习的方法突破建议:(1)复习时,可以先让学生自己想一想本学期学习了哪些知识,然后在小组中互相说一说,并进行相互补充。
最后,教师带领学生一起梳理,帮助学生经历复习的基本过程,感受复习的基本方法,养成梳理知识的习惯。
(2)利用多种形式的表征突出结构性。
如复习时教师可以在黑板上写一个数(45),以“看到这个数你想到了什么?”引领学生复习。
学生可以想到:有45个苹果(基数意义);第45个人(序数意义);4个十和5个一(组成);46前面的那个数或44后面的那个数(数的顺序);四十五(读法);十位上有4个珠子、个位上有5个珠子等等。
还可以想到关于45的运算,如得数是45的加、减法,45加、减一位数,45加、减整十数等。
还可以想到45在生活中的运用等。
2.提高计算能力以及运用所学知识解决简单实际问题的能力突破建议:(1)计算的整理和复习可以采取单一性训练和对比性训练。
如78-30、65-40、82-20等直接口算的单一性训练;如把58-30与58-3放一组,把67-20与67-2放一组进行对比训练,让学生理解虽然减的数中都有3,但由于3所在的位置不同代表的意思不同,体会只有相同的计数单位上的数才能相加、减。
还可以把像14-8、24-8、34-8、44-8、54-8、64-8、74-8、84-8、94-8这样的算式分成一组,让学生先计算,再观察被减数、减数、差之间的变化规律,提高学生计算的正确率。
(2)将计算的复习、人民币的复习、分类与整理的复习等与解决简单的实际问题相结合,通过解决简单的实际问题进一步巩固知识,并加深对知识的理解。
3.增强学习数学的兴趣突破建议:(1)关注学生情感态度的培养,可让学生说说在学习过程中有趣的或者印象深刻的事情有哪些,说说自己用学到的知识解决了哪些问题,有哪些新发现等,让学生感受学习数学的乐趣,获得积极的情感体验。
八年级物理(上)重难点突破1:控制变量法
八年级物理上重难点专题突破1-----控制变量法阅读提升:1、控制变量法:自然界发生的各种现象,往往是错综复杂的。
决定某一个现象的产生和变化的因素常常也很多。
为了弄清事物变化的原因和规律,必须设法把其中的一个或几个因素用人为的方法控制起来,使它保持不变,然后来比较,研究其他两个变量之间的关系,这种研究问题的科学方法就是“控制变量法”。
初中物理实验大多都用到了这种方法,如通过导体的电流I 受到导体电阻R 和它两端电压U 的影响,在研究电流I 与电阻R 的关系时,需要保持电压U 不变;在研究电流I 与电压U 的关系时,需要保持电阻R 不变;影响压力作用效果的因素、影响液体蒸发快慢的因素、探究声音产生的因素、探究液体内部压强的规律、比热容概念的引入等。
2、转换法:一些看不见,摸不着的物理现象,不好直接认识它,我们常根据它们表现出来的看的见、摸的着的现象来间接认识它们。
如根据电流的热效应来认识电流大小,根据磁场对磁体有力的作用来认识磁场等。
3、等效法:在研究物理问题时,有时为了使问题简化,常用一个物理量来代替其他所有物理量,但不会改变物理效果。
如用合力替代各个分力,用总电阻替代各部分电阻,浮力替代液体对物体的各个压力等。
4、类比法:在认识一些物理概念时,我们常将它与生活中熟悉且有共同特点的现象进行类比,以帮助我们理解它。
如认识电流大小时,用水流进行类比。
认识电压时,用水压进行类比,用水流(压)类比电流(压);用水波类比声波。
5、建立理想模型法:在研究磁体的磁场时,引入“磁感线”的概念、表示模型(如太阳系模型);理论模型(如理想气体模型);想象模型(如电场线、磁感线等力线的模型);数学模型(如空间点阵模型)。
控制变量法专题训练例题1:小敏、小颖和小青在玩荡秋千时,感到秋千往返摆动时间有规律。
于是对“哪些因素决定秋千往返摆动的时间”提出下列猜想,小敏猜想:可能由秋千的绳长决定;小颖猜想:可能由人与秋千坐垫的总质量决定;小青猜想:可能由秋千摆动幅度(摆动中人离开中心的最大距离)决定。
人教版三年级数学上册期末复习重难点突破试题含答案3套
人教版三年级数学上册期末复习重难点突破试题含答案3套期末总复习重难点突破卷1拼后的周长与周长的逆运算一、用彩笔描出下列图形的周长。
(4分)二、我会填。
(每空2分,共18分)1.一个正方形的周长是2分米,它的边长是()厘米。
2.一个长方形的宽是5厘米,长是宽的2倍,它的周长是()厘米。
3.一个正方形和一个长方形的周长相等,如果长方形的长是7米,宽是5米,那么这个正方形的边长是()米。
4.下面图形的周长是()分米,列出算式是()。
5.一个长方形的两条相邻边的和是20分米,它的周长是()分米。
6.一个正方形的周长是()米,它的边长是8米。
7.2个边长是4厘米的正方形拼在一起,拼成的图形是()形,它的周长是()厘米。
三、我会辨。
(每题2分,共8分)1.一个正方形的边长是2厘米,3个这样的正方形拼在一起后的图形的周长就列式为2×4×3。
()2.一个长方形的周长是10分米,宽是2分米,求它的长,可以列式是10÷2-2。
()3.用3个相同的正方形去拼长方形,只有一种拼法。
()4.用2个完全一样的长方形去拼图形,只有一种拼法。
()四、我会选。
(每题4分,共12分)1.一个正方形的周长是4米,它的边长是()。
A.1 B.16米C.16 D.1米2.用12个边长是1厘米的正方形拼成一个大长方形,周长最短的长方形()。
A.长12厘米,宽1厘米B.长6厘米,宽2厘米C.长4厘米,宽3厘米3.观察下面两幅图的周长,结论正确的是()。
第一幅第二幅A.两幅图的周长都一样长B.两幅图的周长都不一样长C.只有第一幅图的周长一样长五、计算下列图形的周长。
(每题6分,共18分)六、我会应用。
(每题10分,共40分)1.一根铁丝正好可以围成一个边长是8厘米的正方形。
如果用这根铁丝围成一个长10厘米的长方形,这个长方形的宽是多少?2.有两个完全相同的长方形,长是10厘米,宽是5厘米。
(1)聪聪用它们拼成了一个长方形,这个长方形的周长是多少?(2)明明用它们拼成了一个正方形,这个正方形的周长是多少呢?3.学校举行“我与可爱的小动物”画展,三年级选出20幅作品,每幅作品都是边长为2分米的正方形,现在要把这些作品贴在一起,并在四周贴上花边,怎样设计才能使贴的花边最少?4.一张长12厘米、宽8厘米的长方形纸板,若把它剪成4张同样的小长方形纸板。
人教版四年级数学上册期末总复习重难点突破卷
期末总复习重难点突破卷1几何图形的联系与区别一、我会填。
(每空1分,共17分)1.一根拉紧的线,绷紧的弦,都可以看作();手电筒或太阳射出的光线都可以看作()。
2.()有两个端点;()没有端点。
3.在同一个平面内()的两条直线叫做平行线。
4.()形和()形是特殊的平行四边形。
5.图中有()个三角形,()个平行四边形,()个梯形。
6.上图中线段有()条,直线有()条,射线有()条。
7.我们学过的角按从小到大的顺序排列是锐角<()<()<()<()。
二、我会辨。
(每题2分,共6分)1.两条不相交的直线叫做平行线。
()2.从一点可以画无数条射线,过两点可以画一条射线。
()3.将一张圆形纸对折3次后,可以得到30°的角。
()三、我会选。
(每题3分,共9分)1.下列说法不正确的是()。
A.射线和线段都是直线的一部分B.直角梯形只有一个直角C.在同一平面内,没有两条直线既不相交也不平行2.过直线外一点画已知直线的平行线,可以画()条。
A.1B.2C.无数3.如下图,关于线段AB和线段CD,说法正确的是()。
A.AB平行于CD B.AB不平行于CD C.AB垂直于CD 四、按要求解决。
(共32分)1.给每个钟面画上时针。
(每题3分,共6分)(1)时针与分针形成直角。
(2)时针与分针形成钝角。
2.互相垂直的画“⊥”,互相平行的画“∥”。
(6分)3.下面哪些图形是梯形?画出每个梯形的高,并标出上底、下底、腰和高。
(12分)4.把符合要求的图形填在括号里。
(每题2分,共8分)(1)两组对边分别平行,有四个直角的四边形。
()(2)只有一组对边平行的四边形。
()(3)四条边都相等,四个角都是直角。
()(4)两组对边分别平行的四边形。
()五、动手操作。
(每题8分,共24分)1.用你喜欢的方法画一个60°的角,并标出角各部分的名称。
2.画一个直角梯形。
3.在平行四边形上画一条线段,把这个平行四边形分成两个完全一样的梯形。
人教版小学二年级下册数学 重难点突破卷1附答案
人教版小学二年级下册数学重难点突破卷1一、我会填。
(每题6分,共30分)1.估一估,买这三种商品大约共需()元。
2.有47吨煤,用载重5吨的货车来运,运()次后,还剩2吨。
3.有1600元,买豆浆机用去300元,买冰箱用去900元,还剩()元。
4.除数是9,商比除数小3,则被除数是()。
5.(1) 红队:赢3场输2场,得()分。
(2) 黄队:赢4场输1场,得()分。
二、走进生活,解决问题。
(每题14分,共70分)1.女同学比男同学多花多少钱?2.阳光小学原来有45本儿童画报,又买来18本。
如果每个班分9本,可以分给几个班?3.小芳跳了多少下?4.二年级召开家长会,同学们准备了34把单人椅和6把双人椅。
邀请了50位家长,座位够吗?5.(1) 1双手套比1条毛巾贵多少元?(2) 买1双手套的钱可以买几条毛巾?答案一、1.13002.93.4004.54[点拨] 先求出商,列式是9-3=6,再求被除数,列式是6×9=54。
5.(1)9[点拨] 列式是:3×5-2×3=9(分)。
(2)17二、1.4×(7-3)=16(元)口答:女同学比男同学多花16元钱。
2.(45+18)÷9=7(个)口答:可以分给7个班。
3.40-8+6=38(下)口答:小芳跳了38下。
4.6×2+34=46(位) 46<50口答:座位不够。
[点拨] 每把双人椅能坐2人。
5.(1) 54÷9=6(元)24-6=18(元)口答:1双手套比1条毛巾贵18元。
(2) 24÷6=4(条)口答:买1双手套的钱可以买4条毛巾。
【拓展资料】(一)小学整数知识。
1.整数的意义自然数和0都是整数。
2.自然数我们在数物体的时候,用来表示物体个数的1,2,3叫做自然数。
一个物体也没有,用0表示。
0也是自然数。
3.计数单位一(个)、十、百、千、万、十万、百万、千万、亿都是计数单位。
2021-2022学年沪粤版物理九年级上册重难点突破练习(一)
沪粤版九年级物理上册重难点突破(一)一、计算题1.一款全自动豆浆机的主要结构如图甲,图乙是它的铭牌,其电路原理如图丙。
该豆浆机做一次豆浆需要8min,其正常工作过程中电热管和电动机的工作时间与工作状态如下表所示。
(1)豆浆机正常工作时,电热丝电阻是多少?(2)豆浆机正常工作做一次豆浆,电流做功多少焦?(3)为测定家里电路的实际电压,小明将家里的其它用电器都断开,只让这款豆浆机工作,他观察到在豆浆机的电热丝工作的3min内,家里标有“2000r/kW•h”字样的电能表转盘转了50转,则他家里电路的实际电压是多少?(不考虑温度对电阻的影响)2.如图,电源电压为12V,灯泡L的规格为“6V3W”,滑动变阻器R1上标有“20Ω1A”,R2=10Ω,电流表量程为0∼3A。
将开关S闭合,S1、S2断开,调节变阻器使灯泡正常发光。(1)求灯泡正常发光时的电阻;(2)求滑动变阻器10s内消耗的电能;(3)将开关S、S1、S2都闭合,移动滑片P且电路安全,求R1与R2功率之比的最大值。
3.如图所示的电路中,电源电压保持不变,灯泡上标有“6V 3.6W”(忽略温度对灯泡电阻的影响)当只闭合开关S1,滑动变阻器的滑片P在最右端时,滑动变阻器两端的电压为U1,R2消耗的功率为P2;接着将滑片移到最左端,再闭合开关S3,此时R2消耗的功率为P2´,电流表的示数变化了0.7A;当只闭合开关S2、S3,滑片P在中点时,此时电压表的示数是3V,滑动变阻器两端的电压为U1´。
已知U1:U1´=4:3,P2:P2´=1:9,求:(1)灯泡的电阻;(2)电源电压;(3)通过开关通断,和滑片的移动,求电路中消耗的最大功率与最小功率之比。
4.如图所示的电路中,电源电压保持不变,定值电阻R1=10Ω,R2为滑动变阻器,滑片P位于R2的中间某点A时,(不一定是最中间)R1的电功率为10W,电压表示数为U1,电路中的电流为I1;当滑片从A 点向右端移动距离L后,R1的电功率为2.5W,电压表示数为U2,电路中的电流为I2;当滑片从A点向后,电压表示数为U3,电路中的电流为I3,试求:左端移动距离L2(1)电压表示数U1;(2)电路中的电流I1与电流I2之比;(3)电压表示数U2与U3示数之比;后,R1的电功率。
最新重难点突破-有理数的加减混合运算 (1)
重难点突破-有理数的加减混合运算
一、单项选择题(共8题,共24分)
1.一位“粗心”的同学在做加减运算时,将“-5”错写成“+5”进行运算,这样他得到的结果比正确答案()
A. 少5
B. 少10
C. 多5
D. 多10
2.下面说法中错误的是()A.有理数的加减混合运算都可以写成有理数的加法运算B.-5-(-6)-7不能应用加法的结合律和交换律C.如果a和b都是c的相反数,则 D.有理数的加减混合运算都可以写成有理数的减法运算
3.把前2008个数1,2,3,4,…,2008的每一个数的前面任意填上“+”号或“-”号,然后将它们相加,则所得之结果为()
A. 偶数
B. 奇数
C. 正数
D. 有时为奇数,有时为偶数
4.若p、q是负数,则以下式中其值最大的是()
A. 1-(p-q)
B. 1+(-p-q)
C. 1-(-p+q)
D. 1+(-p+q)
5.下列说法正确的是()A. 两个数之差一定小于被减数 B. 减去一个负数,差一定大于被减数C. 减去一个正数,差一定大于被减
数 D. 0减去任何数,差都是负数6.两个非零有理数的和为正数,那么这两个有理数为() A.都是正数 B.至少有一个为正数 C.正数大于负数 D.正数大于负数的绝对值或都为正数7.把算式
写成省略加号的和的形式,正确的是()
A.
B.
C.
D.
8.某天股票甲开盘价为18元,上午11:30时跌了1.2元,下午收盘时又涨了0.8元,则股票甲这天收盘时价格为()
A. 16元
B. 18.4元
C. 17.6元
D. 20元。
[荐]人教三年级数学上全册重难点突破测试卷-名校版含答案
人教三年级数学上全册重难点突破测试卷-名校版含答案第一单元重难点突破1.< = > < > 2032. 6:30 25 6:553. 10:25 15 10:404.(1)答:上午8:00现代城小区停电了。
【点拨】先看上午8:00在哪个时间段内,再看该时间哪个小区停电了。
(2)他家住在上林苑小区。
4时50分-3时50分=1时答:这个小区还需要1小时才能来电。
5. 第1集下午5:20—下午(5:50)广告下午(5:50)一下午( 5:55)第2集下午(5:55)一下午(6:25)广告下午(6:25 )一下午(6:30)第3集下午(6:30)一下午( 7:00)答:聪聪下午6:40做完作业打开电视时,看到的是动画片。
6.(1)2时40分-2时10分=30分答:三(1)班参观科技展览用30分钟。
(2)答:下午3:10三(2)班在参观科技展览。
(3)2时50分-5分=2时45分答:她最晚下午2:45从教室出发才不会迟到。
(4)我发现每个班参观要30分钟,中间间隔10分钟,所以三(4)班参观时间为下午4:10-4:40。
第二单元重难点突破1. C2. B3. B4. A5. 746. 32-23=9 76-9=67答:正确的结果是67。
7. (1)38-29=9(分)答:①号选手领先9分。
(2)62-38=24(分)58-29=29(分)答:第二轮1号选手得了24分,②号选手得了29分。
8. 把172 看成170,把364看成360,170+360=530(元)530>500,172+364一定大于500。
答:带500元钱不够。
9.(1)把168看成170,把116看成120,170+120=290(元) 290<300168+116一定小于300。
答:买这套衣服够。
(2)把168看成170,把116看成120,170-12 0=50(元) 答:一件上衣比一条裤子大约贵50元钱。
新北师大版六年级数学上册重难点突破卷(含答案)
分数、比、百分数的综合应用重难点突破卷一、我会填。
(每空2分,共18分)1.一本书,看了它的25,已看的和未看的比是( ),未看的占全书的( )%。
2.三个数的平均数是9,这三个数中的最大数是( )。
3.从家到商场,爸爸要走10分,小明要走12分,爸爸与小明的速度比是( )。
4.比300 m 多40%是( )m ,15吨比14吨少( )%。
5.男生人数和女生人数的比是5∶3,男生占全班的( ),女生人数比男生人数少()%。
6.甲、乙两数的比是5∶4,甲比乙多( )%。
二、我会辨。
(对的在括号里画“√”,错的画“×”)(每题1分,共3分)1.两个圆的直径之比是3∶4,它们的周长和面积之比都是3∶4。
( )2.70100和70%表示的意义不一定相同。
( )3.一件衣服先降价10%,然后又降价10%,相当于降价20%。
( )三、我会选。
(把正确答案前的字母填在括号里)(每题3分,共9分)1.在含糖率为5%的糖水中,糖占水的( )。
A.121B.120C.1192.一个直角三角形的三个内角的度数比不可能是( )。
A .1∶2∶3B .2∶3∶5C .2∶3∶43.甲数的倒数是45,乙数的倒数是4,甲、乙两数和的50%是( )。
A .245 B.34 C .3 D.2140四、我会计算。
(共20分)1.直接写出得数。
(每题1分,共8分)14÷73= 2.7÷10%= 3%+3=715×521= 12.5%÷0.125=89÷14= 12-12×12= 78×14÷78= 2.下面各题怎样算简便就怎样算。
(每题3分,共6分)1-⎝ ⎛⎭⎪⎫12-13÷5713÷39+⎝ ⎛⎭⎪⎫126+239×133.解方程。
(每题3分,共6分)1-45x -15=1225-15x =10%五、看图列式计算。
人教版六年级数学上册一、三单元重难点突破。提分秘籍。
六年级数学上册一、三单元重难点突破对比练习一单元三单元1、30kg 的53是( )kg 。
1、( )kg 的53是30kg 。
2、比30kg 多53是( )kg 。
2、30kg 比( )kg 多53。
3、公鸡有240只,母鸡的只数是 3、公鸡有240只,公鸡的只数是 公鸡只数的53,母鸡有几只? 母鸡只数的53,母鸡有几只?4、公鸡有240只,母鸡的只数比 4、公鸡有240只,公鸡的只数比 公鸡多53,母鸡有几只? 母鸡多53,母鸡有几只?5、20kg 是25kg 的()()25kg 是20kg 的()()20kg 比25kg 少()()25kg 比20kg 多()()一单元三单元1、30kg 的53是(18)kg 。
1、( 50 )kg 的53是30kg 。
30×53=18 30÷53=50 或3053=x2、比30kg 多53是( )kg 。
2、30kg 比( 1843 )kg 多53。
30+30×=5348 x+53x=30\x=1843或18.75或 30÷(1+53)=18.753、公鸡有240只,母鸡的只数是 3、公鸡有240只,公鸡的只数是公鸡只数的53,母鸡有几只? 母鸡只数的53,母鸡有几只?公鸡只数(240)×53=母鸡只数 母鸡只数×53=公鸡只数(240)240×53=144(只) 53x=240 或240÷53=4005、公鸡有240只,母鸡的只数比 4、公鸡有240只,公鸡的只数比 公鸡多53,母鸡有几只? 母鸡多53,母鸡有几只?公鸡只数+公鸡只数×53=母鸡只数 母鸡只数+母鸡只数×53=公鸡只数(240) 240+240×53=384(只) x+53x=240母鸡只数×(1+53)=公鸡只数(240)240÷(1+53)=150(只)A 比B 多几分之几指A 比B 多了B 的几分之几。
专题2.8 期末重难点突破训练卷(一)(人教版)(解析版)
2020-2021学年八年级下册期末重难点突破训练卷(一)参考答案与试题解析一.选择题(共10小题,满分30分,每小题3分)1.(3分)下列二次根式中,最简二次根式是()A.√5a2b B.√a2+b2C.√a2D.√18x【分析】利用最简二次根式定义判断即可.【解答】解:A、原式=|a|√5b,不符合题意;B、原式为最简二次根式,符合题意;C、原式=√2a2,不符合题意;D、原式=3√2x,不符合题意.故选:B.【点睛】此题考查了最简二次根式,熟练掌握最简二次根式定义是解本题的关键.2.(3分)三角形的三边分别为a、b、c,由下列条件不能判断它是直角三角形的是()A.a=13,b=14,c=15B.a2﹣b2=c2C.a2=(b+c)(b﹣c)D.a:b:c=13:5:12【分析】根据勾股定理的逆定理逐个判断即可.【解答】解:A、∵a=13,b=14,c=15,∴b2+c2≠a2,即此三角形不是直角三角形,故本选项符合题意;B、∵a2﹣b2=c2,∴b2+c2=a2,即此三角形是直角三角形,故本选项不符合题意;C、∵a2=(b+c)(b﹣c)=b2﹣c2,∴a2+c2=b2,即此三角形是直角三角形,故本选项不符合题意;D、∵a:b:c=13:5:12,∴b2+c2=a2,即此三角形是直角三角形,故本选项不符合题意;故选:A.【点睛】本题考查了勾股定理的逆定理,能熟记勾股定理的逆定理的内容是解此题的关键,注意:如果一个三角形两边的平方和等于第三边的平方,那么这个三角形是直角三角形.3.(3分)如图数轴上的点O表示的数是0,点A表示的数是2,OB⊥OA,垂足为O,且OB=1,以A为圆心,AB长为半径画弧,交数轴于点C,则点C表示的数为()A.−√5B.﹣2+√5C.2−√5D.﹣2−√5【分析】利用勾股定理求出AB的长,可得AB=AC=√5,推出OC=√5−2即可解决问题.【解答】解:在Rt△AOB中,AB=√OB2+OA2=√22+12=√5,∴AB=AC=√5,∴OC=AC﹣OA=√5−2,∵C点在x轴负半轴,∴点C表示的数为2−√5.故选:C.【点睛】本题考查实数与数轴、勾股定理等知识,解题的关键是理解题意,灵活运用所学知识解决问题,属于中考基础题.4.(3分)已知当1<a<2时,代数式√(a−2)2−|1﹣a|的值是()A.﹣3B.1﹣2a C.3﹣2a D.2a﹣3【分析】直接利用二次根式的性质分别化简得出答案.【解答】解:∵当1<a<2时,∴√(a−2)2−|1﹣a|=2﹣a﹣(a﹣1)=2﹣a﹣a+1=﹣2a+3,故选:C.【点睛】此题主要考查了二次根式的性质与化简,正确化简二次根式是解题关键.5.(3分)某手表厂抽查了10只手表的日走时误差,数据如下表所示:则这10只手表的平均日走时误差(单位:秒)是( ) 日走时误差(秒) 0 1 2 3 只数(只) 3 4 2 1A .0B .0.6C .0.8D .1.1【分析】利用加权平均数的定义求解即可. 【解答】解:这10只手表的平均日走时误差是0×3+1×4+2×2+3×110=1.1(秒),故选:D .【点睛】本题主要考查加权平均数,解题的关键是掌握加权平均数的定义.6.(3分)已知在平行四边形ABCD 中,AC =6,E 是AD 上一点,△DCE 的周长是平行四边形ABCD 周长的一半,且EC =4,连接EO ,则EO 的长为( )A .3B .5C .2√5D .√7【分析】根据平行四边形的性质和△DCE 的周长是平行四边形ABCD 周长的一半,可证明OE 是线段AC 的中垂线,根据勾股定理即可求出EO 的长. 【解答】解:∵四边形ABCD 是平行四边形, ∴AC 、BD 互相平分, ∴O 是AC 的中点. ∴OA =OC =12AC =3,∵△DCE 的周长是平行四边形ABCD 周长的一半, ∴△DCE 的周长=CD +CE +DE =CD +AD , ∴CE +DE =AD , ∵AE +DE =AD , ∴AE =CE ,∴OE 是线段AC 的中垂线,∴OE ⊥BD ,∵AE =EC =4,OA =3,∴EO =√AE 2−OA 2=√16−9=√7. 故选:D .【点睛】此题主要考查了平行四边形的性质,中垂线的判定及性质,解决本题的关键是掌握平行四边形的性质.7.(3分)如图,点C 、B 分别在两条直线y =﹣3x 和y =kx 上,点A 、D 是x 轴上两点,若四边形ABCD 是正方形,则k 的值为( )A .3B .2C .23D .32【分析】设点C 的横坐标为m ,则点C 的坐标为(m ,﹣3m ),点B 的坐标为(−3mk ,﹣3m ),根据正方形的性质,即可得出关于k 的分式方程,解之经检验后即可得出结论.【解答】解:设点C 的横坐标为m ,则点C 的坐标为(m ,﹣3m ),点B 的坐标为(−3mk,﹣3m ), 依题意,得:−3mk −m =﹣3m , 解得:k =32,经检验,k =32是原方程的解,且符合题意. 故选:D .【点睛】本题考查了一次函数图象上点的坐标特征以及正方形的性质,利用一次函数图象上点的坐标特征及正方形的性质,找出关于k 的方程是解题的关键.8.(3分)小敏参加了某次演讲比赛,根据比赛时七位评委所给的分数制作了如下表格:平均数/分 中位数/分众数/分 方差/分2 8.88.98.50.14如果去掉一个最高分和一个最低分,那么表格中数据一定不发生变化的是( )A .平均数B .中位数C .众数D .方差【分析】利用平均数、中位数、众数和方差的意义进行判断.【解答】解:如果去掉一个最高分和一个最低分,则平均数、众数可能发生变化,数据的波动性变小,方差变小,而7个数据按由小到大排列,最中间的一个数没有变化,所以数据的中位数一定不发生变化. 故选:B .【点睛】本题考查了方差:方差是反映一组数据的波动大小的一个量.方差越大,则平均值的离散程度越大,稳定性也越小;反之,则它与其平均值的离散程度越小,稳定性越好.也考查了平均数、中位数和众数.9.(3分)如图,在Rt △ABC 中,∠BAC =90°,AB =5,AC =12,P 为边BC 上一动点(P 不与B 、C 重合),PE ⊥AB 于E ,PF ⊥AC 于F ,M 为EF 中点,则AM 的取值范围是( )A .3013≤AM <6 B .5≤AM <12 C .125≤AM <12 D .125≤AM <6【分析】首先证明四边形AEPF 是矩形,因为M 是EF 的中点,推出延长AM 经过点P ,推出EF =AP ,可得AM =12EF =12P A ,求出P A 的最小值可得AM 的最小值,又由AP <AC ,即可求得AM 的取值范围. 【解答】解:在Rt △ABC 中,∵∠BAC =90°,AB =5,AC =12, ∴BC =√52+122=13, ∵PE ⊥AB 于E ,PF ⊥AC 于F , ∴∠PEA =∠PF A =∠EAF =90°, ∴四边形AEPF 是矩形, ∵M 是EF 的中点, ∴延长AM 经过点P , ∴EF =AP , AM =12EF =12P A ,当P A ⊥CB 时,P A =5×1213=6013, ∴AM 的最小值为3013,∵P A <AC , ∴P A <12, ∴AM <6, ∴3013≤AM <6,故选:A .【点睛】此题考查了矩形的判定与性质、勾股定理、直角三角形的斜边上的高的求法,注意当AP ⊥BC 时,AP 最小,且AP <AC .10.(3分)在平面直角坐标系中,解析式为y =√3x +1的直线a ,解析式为y =√33x 的直线b 如图所示,直线a 交y 轴于点A ,以OA 为边作第一个等边三角形△OAB ,过点B 作y 轴的平行线交直线a 于点A 1,以A 1B 为边作第二个等边三角形△A 1BB 1,…顺次这样做下去,第2020个等边三角形的边长为( )A .22019B .22020C .4038D .4040【分析】延长A 1B 交x 轴于D ,A 2B 1交x 轴于E ,根据等边三角形的性质得OA =OD ,A 1B =BB 1,A 2B 1=B 2B 1,直线OB 的解析式为y =√33x ,得出∠BOD =30°,由直线a :y =√3x +1得出第一个等边三角形边长为1,解直角三角形求得OD =√32,BD =12,把x =√32代入y =√3x +1求得A 1的纵坐标,即可求得第二个等边三角形的边长,…,按照此规律得到第三个、第四个等边三角形的边长,从而求得第2020个等边三角形的边长.【解答】解:延长A 1B 交x 轴于D ,A 2B 1交x 轴于E ,如图, ∵△OAB 、△BA 1B 1、△B 1A 2B 2均为等边三角形, ∴OA =OD ,A 1B =BB 1,A 2B 1=B 2B 1, ∵直线OB 的解析式为y =√33x , ∴∠BOD =30°,由直线a :y =√3x +1可知OA =1, ∴OB =1, ∴OD =√32,BD =12,把x =√32代入y =√3x +1得y =52, ∴A 1D =52, ∴A 1B =2, ∴BB 1=A 1B =2, ∴OB 1=3, ∴OE =3√32,B 1E =32, 把x =3√32代入y =√3x +1得y =112, ∴A 2E =112, ∴A 2B 1=4,同理得到A 3B 2=23,…,按照此规律得到第2020个等边三角形的边长为22019, 故选:A .【点睛】本题考查了一次函数图象上点的坐标特征、等边三角形的性质,根据等边三角形的性质找出第n 个等边三角形的边长为2n﹣1是解题的关键.二.填空题(共5小题,满分15分,每小题3分) 11.(3分)要使式子√x+22x−6有意义,则x 的取值范围是 x ≥﹣2且x ≠3 . 【分析】由被开方数为非负数及分母不为0得出关于x 的不等式组,解之可得. 【解答】解:∵式子√x+22x−6有意义,∴{x +2≥02x −6≠0, 解得x ≥﹣2且x ≠3, 故答案为:x ≥﹣2且x ≠3.【点睛】此题主要考查了二次根式有意义的条件,关键是把握被开方数为非负数.12.(3分)如图,若每个小正方形的边长为1,点A 、B 和C 都在格点上,则点C 到AB 的距离为6√105.【分析】根据格点三角形,利用勾股定理求出AB 的长度,然后根据三角形ABC 的面积的不同表达方法,可得出点C 到AB 的距离.【解答】解:由图形可得:AB =√32+12=√10,12BC ×AD =12AB ×CE ,即12×4×3=12×√10×CE , 解得:CE =6√105. 故答案为:6√105. 【点睛】本题考查了三角形的面积及勾股定理的知识,解答本题的关键是根据三角形面积的表达式得出CE 的值,要求我们熟练掌握勾股定理的表达式.13.(3分)将函数y =3x +1的图象平移,使它经过点(﹣2,0),则平移后的函数表达式是 y =3x +6 .【分析】根据平移不改变k的值可设y=3x+b,然后将点(﹣2,0)代入即可得出直线的函数解析式.【解答】解:设平移后的函数表达式是y=3x+b,∵它经过点(﹣2,0),∴0=﹣6+b,解得:b=6.∴平移后的函数解析式为:y=3x+6.故答案为:y=3x+6.【点睛】此题考查了一次函数图形与几何变换,求直线平移后的解析式时要注意平移时k的值不变.14.(3分)如图,在△ABC中,∠ABC=90°,AB=8,BC=6.若DE是△ABC的中位线,延长DE交△ABC的外角∠ACM的平分线于点F,则线段DF的长为8.【分析】根据勾股定理求出AC,根据三角形中位线定理得到DE=12BC=3,DE∥BC,根据角平分线的定义、平行线的性质、等腰三角形的判定定理得到EF=EC=5,结合图形计算,得到答案.【解答】解:在Rt△ABC中,AC=√AB2+BC2=√62+82=10,∵DE是△ABC的中位线,∴DE=12BC=3,DE∥BC,EC=12AC=5,∴∠EFC=∠FCM,∵CF是∠ACM的平分线,∴∠ECF=∠FCM,∴∠EFC=∠ECF,∴EF=EC=5,∴DF=DE+EF=3+5=8,故答案为:8.【点睛】本题考查的是三角形中位线定理、平行线的性质、角平分线的定义、等腰三角形的判定,掌握三角形的中位线平行于第三边,且等于第三边的一半是解题的关键.15.(3分)如图,∠MAN=90°,点C在边AM上,AC=4,点B为边AN上一动点,连接BC,△A′BC 与△ABC关于BC所在直线对称,点D,E分别为AC,BC的中点,连接DE并延长交A′B所在直线于点F,连接A′E.当△A′EF为直角三角形时,AB的长为4√3或4.【分析】当△A′EF为直角三角形时,存在两种情况:①当∠A'EF=90°时,如图1,根据对称的性质和平行线可得:A'C=A'E=4,根据直角三角形斜边中线的性质得:BC=2A'E=8,最后利用勾股定理可得AB的长;②当∠A'FE=90°时,如图2,证明△ABC是等腰直角三角形,可得AB=AC=4.【解答】解:当△A′EF为直角三角形时,存在两种情况:①当∠A'EF=90°时,如图1,∵△A′BC与△ABC关于BC所在直线对称,∴A'C=AC=4,∠ACB=∠A'CB,∵点D,E分别为AC,BC的中点,∴D、E是△ABC的中位线,∴DE∥AB,∴∠CDE=∠MAN=90°,∴∠CDE=∠A'EF,∴AC∥A'E,∴∠ACB=∠A'EC,∴∠A'CB=∠A'EC,∴A'C=A'E=4,Rt△A'CB中,∵E是斜边BC的中点,∴BC=2A'E=8,由勾股定理得:AB2=BC2﹣AC2,∴AB=√82−42=4√3;②当∠A'FE=90°时,如图2,∵∠ADF=∠A=∠DFB=90°,∴∠ABF=90°,∵△A′BC与△ABC关于BC所在直线对称,∴∠ABC=∠CBA'=45°,∴△ABC是等腰直角三角形,∴AB=AC=4;综上所述,AB的长为4√3或4;故答案为:4√3或4;【点睛】本题考查了三角形的中位线定理、勾股定理、轴对称的性质、等腰直角三角形的判定、直角三角形斜边中线的性质,并利用分类讨论的思想解决问题.三.解答题(共8小题,满分75分)16.(8分)计算:(1)2√18−√50+12√32;(2)(√5+√6)(√5−√6)﹣(√5−1)2.【分析】(1)先化为最简二次根式,然后根据二次根式的运算法则即可求出答案.(2)根据完全平方公式以及平方差公式即可求出答案.【解答】解:(1)原式=6√2−5√2+2√2=3√2.(2)原式=5﹣6﹣(5﹣2√5+1)=﹣1﹣(6﹣2√5)=﹣1﹣6+2√5=﹣7+2√5.【点睛】本题考查二次根式的运算,解题的关键是熟练运用二次根式的运算法则,本题属于基础题型.17.(9分)中考体育测试前,某区教育局为了了解选报引体向上的初三男生的成绩情况,随机抽测了本区部分选报引体向上项目的初三男生的成绩,并将测试得到的成绩绘成了下面两幅不完整的统计图:请你根据图中的信息,解答下列问题:(1)写出扇形图中a=25%,并补全条形图;(2)在这次抽测中,测试成绩的众数和中位数分别是5个、5个.(3)该区体育中考选报引体向上的男生共有1800人,如果体育中考引体向上达6个以上(含6个)得满分,请你估计该区体育中考中选报引体向上的男生能获得满分的有多少名?【分析】(1)用1减去其他天数所占的百分比即可得到a的值,用360°乘以它所占的百分比,即可求出该扇形所对圆心角的度数;(2)根据众数与中位数的定义求解即可;(3)先求出样本中得满分的学生所占的百分比,再乘以1800即可.【解答】解:(1)扇形统计图中a=1﹣30%﹣15%﹣10%﹣20%=25%,设引体向上6个的学生有x人,由题意得x 25%=2010%,解得x=50.条形统计图补充如下:(2)由条形图可知,引体向上5个的学生有60人,人数最多,所以众数是5;共200名同学,排序后第100名与第101名同学的成绩都是5个,故中位数为(5+5)÷2=5 (3)50+40200×1800=810(名).答:估计该区体育中考选报引体向上的男生能获得满分的同学有810名. 故答案为:25;5,5.【点睛】本题为统计题,考查众数与中位数的意义.一组数据中出现次数最多的数据叫做众数;将一组数据从小到大(或从大到小)重新排列后,最中间的那个数(或最中间两个数的平均数)叫做这组数据的中位数.也考查了条形统计图、扇形统计图与用样本估计总体.18.(9分)如图,已知等腰三角形ABC 的底边BC 长为10,点D 是AC 上的一点,其中BD =8,CD =6. (1)求证:BD ⊥AC ; (2)求AB 的长.【分析】(1)根据勾股定理的逆定理即可得到结论;(2)设AB =x ,则AB =AC =x ,得到AD =x ﹣6,根据勾股定理列方程即可得到结论. 【解答】(1)证明:∵BC =10,BD =8,CD =6, ∴BD 2+CD 2=82+62=102=BC 2, ∴∠BDC =90°,∴BD⊥AC;(2)解:设AB=x,则AB=AC=x,∵CD=6,∴AD=x﹣6,∵AB2=BD2+AD2,∴x2=82+(x﹣6)2,解得:x=25 3,∴AB=25 3.【点睛】此题主要考查了勾股定理,以及勾股定理逆定理,关键是掌握勾股定理的逆定理:如果三角形的三边长a,b,c满足a2+b2=c2,那么这个三角形就是直角三角形.19.(9分)如图,在四边形ABCD中,AB∥DC,AB=AD,对角线AC,BD交于点O,AC平分∠BAD,过点C作CE⊥AB交AB的延长线于点E,连接OE.(1)求证:四边形ABCD是菱形;(2)若AB=2√5,BD=4,求OE的长.【分析】(1)先判断出∠OAB=∠DCA,进而判断出∠DAC=∠DCA,得出CD=AD=AB,即可得出结论;(2)先判断出OE=OA=OC,再求出OB=2,利用勾股定理求出OA,即可得出结论.【解答】解:(1)∵AB∥CD,∴∠OAB=∠DCA,∵AC为∠DAB的平分线,∴∠OAB=∠DAC,∴∠DCA=∠DAC,∴CD=AD=AB,∵AB∥CD,∴四边形ABCD是平行四边形,∵AD=AB,∴▱ABCD是菱形;(2)∵四边形ABCD是菱形,∴OA=OC,BD⊥AC,∵CE⊥AB,∴OE=OA=OC,∵BD=4,∴OB=12BD=2,在Rt△AOB中,AB=2√5,OB=2,∴OA=√AB2−OB2=4,∴OE=OA=4.【点睛】此题主要考查了菱形的判定和性质,平行四边形的判定和性质,角平分线的定义,勾股定理,判断出CD=AD=AB是解本题的关键.20.(9分)某班数学兴趣小组对函数y=||x|﹣2|的图象和性质进行了探究,探究过程如下,请补充完整.(1)自变量x的取值范围是全体实数,x与y的几组对应值列表如下:x…﹣3﹣2﹣1012345…y…1012m0123其中,m=1;(2)根据上表的数据,在如图所示的平面直角坐标系中描点,并画出了函数图象的一部分,请画出该函数图象的另一部分;(3)方程||x|﹣2|=3的解是±5;(4)关于x的方程||x|﹣2|=a有4个实数解,则a的取值范围是0<a<2.【分析】(1)将x=1代入函数解析式中求出y值,即可得出结论;(2)根据表格数据,描点补充完图形;(3)根据函数图象,此题得解;(4)根据函数图象即可求得.【解答】解:(1)当x=1时,y=||x|﹣2|=1,∴m=1,故答案为:1.(2)根据给定的表格中数据描点画出图形,如图所示.(3)观察函数图象,可得方程||x|﹣2|=3的解是±5,故答案为±5.(4)①关于x的方程||x|﹣2|=a有4个实数解,则a的取值范围是0<a<2,故答案为:0<a<2.【点睛】本题考查了一次函数的图象和性质,根据题意画出图形,利用数形结合解决问题是解题的关键.21.(10分)某工厂有甲种原料130kg,乙种原料144kg.现用这两种原料生产出A,B两种产品共30件.已知生产每件A产品需甲种原料5kg,乙种原料4kg,且每件A产品可获利700元;生产每件B产品需甲种原料3kg,乙种原料6kg,且每件B产品可获利900元.设生产A产品x件(产品件数为整数件),根据以上信息解答下列问题:(1)生产A ,B 两种产品的方案有哪几种;(2)设生产这30件产品可获利y 元,写出y 关于x 的函数解析式,写出(1)中利润最大的方案,并求出最大利润.【分析】(1)根据两种产品所需要的甲、乙两种原料列出不等式组,然后求解即可;(2)根据总利润等于两种产品的利润之和列式整理,然后根据一次函数的增减性求出最大利润即可. 【解答】解:(1)根据题意得:{5x +3(30−x)≤1304x +6(30−x)≤144,解得18≤x ≤20, ∵x 是正整数, ∴x =18、19、20, 共有三种方案:方案一:A 产品18件,B 产品12件, 方案二:A 产品19件,B 产品11件, 方案三:A 产品20件,B 产品10件;(2)根据题意得:y =700x +900(30﹣x )=﹣200x +27000, ∵﹣200<0,∴y 随x 的增大而减小, ∴x =18时,y 有最大值,y 最大=﹣200×18+27000=23400元.答:利润最大的方案是方案一:A 产品18件,B 产品12件,最大利润为23400元.【点睛】本题考查了一次函数的应用,一元一次不等式组的应用,读懂题目信息,准确找出题中的等量关系和不等量关系是解题的关键.22.(10分)在菱形ABCD 中,∠ABC =60°,点P 是射线BD 上一动点,以AP 为边向右侧作等边△APE ,点E 的位置随着点P 的位置变化而变化.(1)如图1,当点E 在菱形ABCD 内部或边上时,连接CE ,BP 与CE 的数量关系是 BP =CE ,CE 与AD 的位置关系是 AD ⊥CE ;(2)当点E 在菱形ABCD 外部时,(1)中的结论是否还成立?若成立,请予以证明;若不成立,请说明理由(选择图2,图3中的一种情况予以证明或说理);(3)如图4,当点P 在线段BD 的延长线上时,连接BE ,若AB =2√3,BE =2√19,求四边形ADPE 的面积.【分析】(1)如图1中,结论:PB =EC ,CE ⊥AD .连接AC ,想办法证明△BAP ≌△CAE 即可解决问题; (2)结论仍然成立.证明方法类似;(3)首先证明△BAP ≌△CAE ,解直角三角形求出AP ,DP ,OA 即可解决问题; 【解答】解:(1)如图1中,结论:PB =EC ,CE ⊥AD . 理由:连接AC .∵四边形ABCD 是菱形,∠ABC =60°,∴△ABC ,△ACD 都是等边三角形,∠ABD =∠CBD =30°, ∴AB =AC ,∠BAC =60°, ∵△APE 是等边三角形, ∴AP =AE ,∠P AE =60°, ∵∠BAC =∠P AE , ∴∠BAP =∠CAE , {AB =AC∠BAP =∠CAE AP =AE,∴△BAP ≌△CAE ,∴BP =CE ,∠ABP =∠ACE =30°, 延长CE 交AD 于H , ∵∠CAH =60°, ∴∠CAH +∠ACH =90°, ∴∠AHC =90°,即CE ⊥AD . 故答案为PB =EC ,CE ⊥AD .(2)结论仍然成立.理由:选图2,连接AC 交BD 于O ,设CE 交AD 于H . ∵四边形ABCD 是菱形,∠ABC =60°,∴△ABC ,△ACD 都是等边三角形,∠ABD =∠CBD =30°, ∴AB =AC ,∠BAC =60°, ∵△APE 是等边三角形, ∴AP =AE ,∠P AE =60°, ∴∠BAP =∠CAE . {AB =AC∠BAP =∠CAE AP =AE, ∴△BAP ≌△CAE ,∴BP =CE ,∠PBA =∠ACE =30°, ∵∠CAH =60°, ∴∠CAH +∠ACH =90°, ∴∠AHC =90°,即CE ⊥AD .选图3,连接AC 交BD 于O ,设CE 交AD 于H . ∵四边形ABCD 是菱形,∠ABC =60°,∴△ABC ,△ACD 都是等边三角形,∠ABD =∠CBD =30°, ∴AB =AC ,∠BAC =60°, ∵△APE 是等边三角形, ∴AP =AE ,∠P AE =60°, ∴∠BAP =∠CAE . {AB =AC∠BAP =∠CAE AP =AE, ∴△BAP ≌△CAE ,∴BP =CE ,∠ABP =∠ACE =30°, ∵∠CAH =60°, ∴∠CAH +∠ACH =90°, ∴∠AHC =90°,即CE ⊥AD .(3)△BAP ≌△CAE ,由(2)可知EC ⊥AD ,CE =BP , 在菱形ABCD 中,AD ∥BC , ∴EC ⊥BC ,∵BC =AB =2√3,BE =2√19,在Rt △BCE 中,EC =√(2√19)2−(2√3)2=8, ∴BP =CE =8,∵AC 与BD 是菱形的对角线, ∴∠ABD =12∠ABC =30°,AC ⊥BD , ∴BD =2BO =2AB •cos30°=6,∴OA =12AB =√3,DP =BP ﹣BD =8﹣6=2,∴OP =OD +DP =5,在Rt △AOP 中,AP =√AO 2+OP 2=2√7,∴S 四边形ADPE =S △ADP +S △AEP =12×2×√3+√34×(2√7)2=8√3.【点睛】本题考查四边形综合题、菱形的性质、等边三角形的判定和性质、全等三角形的判定和性质、勾股定理、解直角三角形、锐角三角函数等知识,解题的关键是正确寻找全等三角形解决问题,学会添加常用辅助线,构造全等三角形解决问题,属于中考压轴题.23.(11分)如图,在平面直角坐标系中,直线l 1:y =﹣2x +1与y 轴交于点A ,直线l 2与y 轴交于点B (0,﹣2),交直线l 1于点C ,点C 纵坐标为﹣1,点D 是直线l 2上任意一点,过点D 作x 轴的垂线,交直线l 1于点E ,(1)求直线l 2的解析式;(2)当DE =2AB 时,求D 点坐标;(3)点F 是y 轴上任意一点,当△DEF 是等腰直角三角形时,请直接写出D 点坐标.【分析】(1)用待定系数法即可求解;(2)DE =2AB ,则|m ﹣2+2m ﹣1|=6,即可求解;(3)分∠DEF (或∠EDF )为直角、∠DFE 为直角两种情况,利用数形结合分别求解即可.【解答】解:(1)将点C 的纵坐标代入y =﹣2x +1,即﹣1=﹣2x +1,解得x =1,则点C (1,﹣1),设直线l 2的表达式为y =kx +b ,则{−1=k +b b =−2,解得{k =1b =−2, 故直线l 2的表达式为y =x ﹣2;(2)∵直线l 1:y =﹣2x +1与y 轴交于点A ,则点A (0,1),则AB =1+2=3,设点D (m ,m ﹣2),则点E (m ,﹣2m +1),∵DE =2AB ,故|m ﹣2+2m ﹣1|=6,解得m =﹣1或3,故点D 的坐标为(﹣1,﹣3)或(3,1);(3)①当∠DEF (或∠EDF )为直角时,则DE =EF ,即|m |=|m ﹣2+2m ﹣1|,解得m =32或34, 故点D 的坐标为(32,−12)或(34,−54); ②当∠DFE 为直角时,∵△DEF 是等腰直角三角形,∴点F 到DE 的距离等于12DE ,即|m |=12|m ﹣2+2m ﹣1|, 解得m =3或35, 故点D 的坐标为(3,1)或(35,−75), 综上,点D 的坐标为(32,−12)或(34,−54)或(3,1)或(35,−75). 【点睛】本题考查的是一次函数综合运用,涉及到一次函数的性质、等腰直角三角形的性质等,其中(2)、(3),都要注意分类求解,避免遗漏.。
人教版小学数学二年级下册重难点突破试题全套
人教版小学数学二年级下册重难点突破卷1一、我会填。
(每题6分,共30分)1.估一估,买这三种商品大约共需()元。
2.有47吨煤,用载重5吨的货车来运,运()次后,还剩2吨。
3.有1600元,买豆浆机用去300元,买冰箱用去900元,还剩()元。
4.除数是9,商比除数小3,则被除数是()。
5.(1) 红队:赢3场输2场,得()分。
(2) 黄队:赢4场输1场,得()分。
二、走进生活,解决问题。
(每题14分,共70分)1.女同学比男同学多花多少钱?2.阳光小学原来有45本儿童画报,又买来18本。
如果每个班分9本,可以分给几个班?3.小芳跳了多少下?4.二年级召开家长会,同学们准备了34把单人椅和6把双人椅。
邀请了50位家长,座位够吗?5.(1) 1双手套比1条毛巾贵多少元?(2) 买1双手套的钱可以买几条毛巾?答案一、1.13002.93.4004.54[点拨] 先求出商,列式是9-3=6,再求被除数,列式是6×9=54。
5.(1)9[点拨] 列式是:3×5-2×3=9(分)。
(2)17二、1.4×(7-3)=16(元)口答:女同学比男同学多花16元钱。
2.(45+18)÷9=7(个)口答:可以分给7个班。
3.40-8+6=38(下)口答:小芳跳了38下。
4.6×2+34=46(位) 46<50口答:座位不够。
[点拨] 每把双人椅能坐2人。
5.(1) 54÷9=6(元)24-6=18(元)口答:1双手套比1条毛巾贵18元。
(2) 24÷6=4(条)口答:买1双手套的钱可以买4条毛巾。
重难点突破卷2一、我会填。
(每题6分,共30分)1.小刚、小强和小丁在100米赛跑中取得了前三名的成绩。
已知小刚不是第一名,小强不是前两名。
第一名是()。
2.甲、乙、丙三个小朋友分别戴着1顶红帽子、1顶蓝帽子和1顶黄帽子,甲看见1人戴红帽子,1人戴蓝帽子,那么甲戴()帽子。
《表内乘法(一)》重难点突破
《表内乘法(一)》重难点突破
一、理解乘法运算的意义
突破建议:乘法与加法的关系是非常密切的,乘法是加法的简便运算。
通过3个层次来理解了乘法运算的意义。
(1)动作水平。
用小棒摆一摆3个4、4个3,写出相应的加法算式,感受相同加数与个数的区别。
(2)映象水平。
教师出示直观图片,学生概括出“几个几”,再写出加法、乘法算式。
(3)符号水平。
将求几个相同加数的和的算式直接改为乘法算式。
如:6+6+6=()×()=()×()
二、理解相同数相加与乘法的关系
突破建议:
(1)比较3+3+3+3+3=15与3×5=15,这两个算式的数据有何不同?第二个算式的“5”表示什么意义?你喜欢哪一种算式?为什么?(2)为什么“×”和“+”看齐来很像但又不一样?
(3)根据表述写算式。
2个4相加2与4相乘2个4相乘
三、理解乘法口诀所表示的意义
突破建议:
经历逐步累加几个5的计算的过程,通过箭头表示累加的过程,并反复追问:“几个5相加得数是多少?”写出相应的乘法算式,引出规范的乘法口诀,体验乘法口诀简洁、规范、朗朗上口的特点。
注
意:在书写乘法口诀时运用汉字;乘法口诀将较小的乘数放在前面;采用“小九九”减轻了学习负担。
四、熟记5、2、3、4的乘法口诀。
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重难点突破练习(1)英语学科考试时间:2020.1.21考试时间:60分钟总分:100分一.单项选择(1-10题为每题1分,11-30为每题2分,共50分)1. Things of ____kind come together; people of ____ kind fall into ____ same group.A. a, the, theB. a, a, theC. the, the, theD. a, a, a2. ____ teacher of my grandfather’s will come tomorrow. I’m wondering how old ____ man he should be.A. The, aB. A, aC. A, theD. The, the3. Even on holidays, he preferred doing something ____ doing nothing.A. withoutB. thanC. rather thanD. to4. Her hair became gray ___ the passing of the years.A. inB. forC. atD. with5. I won’t go unless______A.to inviteB.to be invitedC.invitedD. being invited6. ________,she doesn’t work hard.A. Being honestB. To be honestC. HonestD. Honesty7. At six o’clock in the evening when a cat ran through a truck it narrowly escaped ____ over.A. runningB. to be runC. from runningD. being run8.A special committee will________ the air crash.A look atB look forC look intoD look after9. I think that it is the experience ___ he has gained while working abroad during the 1990s ____ has made him succeed in managing the company.A. that, whichB. /, thatC. with which, thatD. which, which10. It was in the small house ___ was built with stones by his father ____ he spent his childhood.A. which, thatB. that, whereC. which, whichD. that, which11. ---Are all the titles of the articles_____ in the contents?---Yes, all ____.A.listed; includedB. listing, includesC. listed, includingD. being listed, being includedA.stickingB. adoptingC. accustomingD. adapting12. We believe __ you have devoted yourself ____ sure to come true.A. that, isB. all that, to beC. that all, areD. what, to is13. With the prices ____, people in poor areas find it difficult to ____ proper health care.A. rising, have access toB. raising, have access toC. raised, have accesses toD. rose, have access to14.--- How are you doing now?--- Very well. I am __ to college life quite easily.15.—My old tyre exploded,can you________ it with a new one? —Certainly,wait a minute.A.take the place of B.replace C.take place D.in place of16. She likes to use words ______ is clear to her.A. of which the meaningB. of which meaningC. whose of meaningD. meaning of which17.The river ________ at least 50 meters in width can be swum acrosswithin minutes.A.measuredB. measuresC. measuringD.being measured18. I’d like to take some pictures ____ stands the old tower.A. whereB. thatC. at whichD. there19.I’m wondering ___ it is ____ has made Irene ___ she is today.A.what; what; thatB. what; that; whatC. what; that; thatD. that; that; what20. It is ____ that he is a writer of ___.A. sure, hopeB. certain, hopeC. certain, promiseD. sure, promise21. The new president will ______ his new responsibility in three days.A. accessB. assureC. assumeD. address22. The boy first showed ______ as an athlete in grade school.A. phenomenonB. possessionC. promiseD. principle23. Nowadays, many people walk or cycle to work the government calling for living a low-carbon lifestyle to deal with global warming.A. in charge ofB. in relation toC. in addition toD. in response to24. The headmaster will a speech to the visiting foreign teachers this afternoon.A. declareB. accelerateC. addressD. applaud25. After the professor _______ the project made a comment on the report, the media all focused on it, causing a heated discussion nationwide.A. opposed to carrying outB. opposed carrying outC. was opposed to carrying outD.was opposed carrying out26. “Why did he let you repeat his instruction time and time again?”“____ that I remembered what was __ after he went out.”A. To make sure, to doB. Making sure, to be doneC. To see to it, to be doneD. seeing to, done27. News reports say peace talks between the two countries have __ with no agreement reached.A. turned downB. held downC. choke downD. broken down28.I kept __ the incident, asking myself again and again how it could have happened.A. chewing onB. sticking toC. referring toD. relying on29. True human happiness should be, as he _______, complete.A. made itB. got itC. put itD. named it30. In desperation, Mrs Jones had to ______ an operation on her right knee to relievethe pain.A. contribute toB. correspond toC. subscribe toD. submit to二.语法填空(共两题,每题15分,每空1.5分,共30分)(一)Stress: Good or Bad?Stress used to be an almost unknown word, but now that we are used to talking about it, I have found that people are beginning to get stressed about being stressed.In recent years, stress 31 (regard) as a cause of a whole range of medical problems, from high blood pressure to mental illness. But like so many other things, it is only too much stress32 does you harm. It is time you considered that if there were no stress in your life, you would achieve a little. If you are stuck at home with no stress, then your level of performance will be low. Up to a certain point, the more stress you are under, the 33 (good) your performance will be. Beyond a certain point, though, further stress will only lead34 exhaustion, illness and finally a breakdown. You can tell when youare over the top and on the downward slope, by asking yourself35 number of questions. Do you, for instance, feel that too much is being expected of 36 , and yet find it impossible to say no? Do you find yourself getting impatient or37 (annoy) with people over unimportant things? If the answer to all those questions is yes, you had better 38 (control) your stress, as you probably are under more stress than is good for you.To some extent you can control the amount of stress in your life. Doctors have worked out a chart showing how much stress is involved in a 39 (various) of events. Getting married is 50, pregnancy 40, moving house 20, Christmas 12, etc. If the total stress in your life is over 150, you are twice as likely40 (get) ill.(二)take care of us.complete stop.43.____________ (weigh)126 kilos, the woman had great difficulty walking about.45.__________(fight) against cancer for many years, Steve Jobs, the co-founder of Apple, who died at the age of fifty-six, made technology fun.47.___________(compare) to her sister, she was indeed very fortunate and happy.factory was going to shut down.for his country.三.短文改错(共两题,每题10分,每处错误一分,共20分)(一)I am grateful to my English teacher Susan, at whose help I couldn't have won first prize in the English Talent Competition for high school students last week.I used to be poorly in speaking English. I was too shy to speak in class. Since she teaches us last term, she has been encouraging him to overcome fear and speak out in class. Thanks to her, I have made great progresses. Besides, I practiced severaltime in the front of her.It was her advice which made me a better speaker and full of confidence.Nevertheless, I owe my success to her.Susan set a good example to me. I am determined to become an English teacher when I grow up.(二)Here are good news for you. A famous Opera, Butterfly Lovers, will put on this Saturday. Butterfly Lovers is one of the most traditional love story. I know you show great interest in Chinese culture, especially for the local operas. I hope this opportunity will not only make you happy, but also satisfies your interest in Chinese opera. If you can come, I suggest have a look at the museum near the theater after watching the opera. There, I believe, I can know the history of many Chinese operas, which can decrease your command of knowledge about Chinese traditional operas. I'm looking forward to receiving your earlier reply.。