5、已知函数，则　　　　　　 (　　 )

A.4　　　　　　　　　　　　　　　 B. 　　　　　　　　　　　　　　　　　　 C.-4　　　　　　　　　　　　　　　 D-

4、设，则a，b，c的大小关系是(　　 )

A、a＞c＞b　　　 B、a＞b＞c　　 C、c＞a＞b　　 D、b＞c＞a

3、对于实数，“”是“”的　　　　 　　(　　 )

A．充分不必要条件 B．必要不充分条件

C．充要条件　　　　　　　　 　　 D．既不充分也不必要条件

2、命题“对任意的”的否定是　　　　 (　　 )

A.不存在　 　B.存在

C.存在　　 　D. 对任意的　

1、已知全集则　 (　　 )

　　　　　　 A．　　 B．　　　　 C．　　　　　 D．

　 根据上下文和括号里的汉语提示，在下面的空白处写出正确的单词和短语，使短文意思完整。

　 When you laugh, you will 1 ______(张开) your mouth and your teeth. The healthier those teeth are, the happier you look. Why is that?

　 It’s 2 _______(因为) your teeth are important in many ways. If you take care of them, they’ll help to take care of you. Strong, healthy teeth help you eat the right food to help you grow. They also help you speak clearly.

　 You can take care of your teeth by doing like these:

　 Brush your teeth 3_______ (一日两次) after breakfast and before bedtime. If you can, brush 4 _______(午饭后) or after eating sweet cakes.

　 Brush all of your teeth, not just the front ones. Spend some time on the teeth along the sides and in the back.

　 Take your time while brushing. Spend 5_______ (至少) 3 minutes each time you brush.

　 Be sure your toothbrush is soft(柔软的). Ask your parent to help you get a new toothbrush 6 ________(每三个月).

　 Learn how to floss(用牙线清理) your teeth, which is a very important way to keep them healthy. It feels strange when you do it at first, but soon you’ll 7 _____(习惯于) doing it. The floss gets rid of food that’s hidden between your teeth.

　 Brushing and flossing 8 ______(保持) your teeth healthy. You also need to care about what you eat and drink. Eat 9 ______(许多) fruits and vegetables and drink water 10_______ (代替) drinks.

1. open　 张开嘴的“张开”应用open。

2. because 要回答前面why提出的问题，应用because。

3. twice a day 这是英语常见的一种表示方法。

4. after lunch after之后常常跟一个时间点，lunch可看作一个时间点。

5. at last 这是一个固定的短语

6. every three months every之后如果有大于一的数词来修饰名词，这个名词用复数形式。又如：every three days, every four years。

7. be/ get used to 这也是一个习惯用语，后接名词或定名词。

8. keep “keep somebody/ something +形容词”是一个常见句型。

9. lots of / a lot of / many 这几个限定词都可用来修饰可数名词的复数。

10. instead of 这是一个短语介词，后接名词活动名词。

[满分演练]

　　　　　　　　　　　　　 (1)

Everyone needs friends. We all like to feel close to someone. It is nice to have a friend to talk, laugh, and do things with. Surely, there are times when we need to be alone. We don't always want people1________(周围). But we would feel lonely if we never had a friend.

No two people are just the same. Sometimes friends don't 2_________(相处得好). That doesn't mean that they no longer like 3_________(互相). Most of the time they will make up and 4__________(继续)being friends.

Sometimes friends move away. Then we feel very sad. We 5_______(想念) them very much. But we call them and write to them. It could be that we would even see them again. And we can 6__________(结交新朋友). It is surprising to find out how much we like new people when we get to know them.

Families sometimes name their children after a close friend. 7_________(许多地方)are named after men and women who have been friendly to people in a town. Some libraries are named this way. So are some schools. We 8_______(想起)these people when we go to these places.

There's more good news for people who have friends. They live 9________(长一些)than people who don't. Why? It could be that they are happier. Being happy helps you stay well. Or it could be just knowing that someone cares. If someone cares about you, you take better care of 10________(你自己).

　　　　　　　　　　　　　　　 (2)

　　 Most great inventors often met with much trouble in their work. Before they could succeed, they had to overcome 1_________(数以千计的)difficulties which were put in their way. The following is one of such examples.

　　 George Stephenson (1781~~1848), a 2__________ (著名的)British inventor made the first train in 1825, using a stream engine. When he was experimenting with the engine 3________ (在火车上), he met with troubles from the government, the newspapers and the gentlemen in the country. They said that the 4________ (噪音)and the smoke would kill cows, horses and sheep, that the engine would burst or that the hot coals from it would set fire to their houses. People believe 5___________ (他们说的话).

　　 George Stephenson told the people that the train could go on small rails, could pull carriages 6________ (装满) goods and passengers and that there was no great danger to them. It was a very difficult matter for him to make them believe. 7________ (然而), after some time, he was able to do it, and the first train, that was driven by George Stephenson himself proved what he had said. On the train there was a new steam engine. It was invented by him, and was proved a complete 8_______ (成功).

　　 The first day when the train ran on the rails, people along the way heard the noise of the train in the distance, and saw it running quickly to them. They thought it was a genie. They ran quickly back home for fear and closed their doors tightly. They did not dare to 9________ (出来)until it had passed. 10________ (一周以后)an old woman still said that her hen had been so frightened that it hadn't laid any eggs for three days.

[练习答案]

　　　　　　　　　　　 　　(3)

Most of American businesses are open five days a week. American school children attend school five days a week as well.

　　 American families usually have a 　1 ______(两天)weekend. The weekend is Saturday and Sunday. Over the weekend people spend their time 　2 _______ (以许多不同的方式) . Many families enjoy weekends 　3 ______(一起) . They may go shopping, go for a drive or visit friends. They may also invite friends over and 　4 ______ (聚会) at home. Many American families participate(参加)in sports during the weekend. 　5 _______ (跑步), biking, playing volleyball and swimming　 　6 _____ (流行)in summer. Skiing and skating are the 　7 _____　 (最喜爱的) winter sports.

　　 Weekends are also a time for American families to work on something in their yards or in 　8 ______(他们的) houses. Many families plant flowers and have vegetable gardens. Some families use the weekends 　9 _______(粉刷)or repair their houses. 　10 ______(对大部分美国人来说), weekends are very busy.

　 　　　　　　　　　　　　　(4)

　　 Perhaps more than any other people, Americans have come to depend on their cars. The family car 　1 _________(一直是) a common thing 　2 _______(从……以来) the early twentieth century, and it has changed American life. Many people have moved 　3 _______(外面) of the large cities to the suburbs. Some Americans spend 　4 ________(每天两小时) or more in their cars 　5 _______ (去上班) and home again. Cars have become the 　6 _______ (工具) of transportation for most Americans going shopping, and even going on vacations.

　　 Americans 　7 ______(过去常常) like big cars, and gasoline used to be very inexpensive. Recently, 　8 _______(然而), the cost of gasoline has increased, smaller cars have become 　9 _______(更常见). Also foreign cars have become very common. Americans have bought 　10 _______(大量的)Japanese and German cars. They have bought cars from several other countries as well.

　　　　　　　　　　　　　 (5)

　　 Each morning a rich man found a poor man sitting on a park bench(长凳). The poor man always sat there, 1___________ (看着)the big hotel in which the rich man lived. 2_________(有一天)the rich man got out of his car and said to the poor man, "Excuse me, but I just want to know why you sit here and look at my hotel 3_________ (每天早晨)." "Sir," said the poor man, "I am a failure. I have no money, no home. I sleep 4________ (在这条长凳上), and every night I dream(梦想)that one day I'll sleep in that hotel." The rich man said, "Tonight your dream will 5________ (变为现实). I'll pay for the best room in that hotel for you a whole month."

　　 6_________ (几天以后), the rich man went by the poor man's room to ask him how he was enjoying himself. 7___________ (使他惊讶的是), he found that the man had 8__________ (搬出了)the hotel, back to his park bench. When the rich man asked why, the poor man said, "You see, when I'm down here sleeping on my bench, I dream I'm up there, 　9____________ (在那个大宾馆里). It's a wonderful dream. But when I was up there, I dreamed I was back to this cold bench. It was a terrible dream, and I couldn't get any sleep 10________ (根本)."

　　　　　　　　　　　　 (6)

On October 12, 1989, some Chinese scientists were working at the computers to 1________ (寻找)the information they needed. Suddenly they saw a lot of very bright spots crossing the computers’ screens. 2__________(同时), they stopped their work to check some parts of the computers. To their horror, they 3___________ (发现)that most of their stored information was got rid of by computer viruses! Obviously all these computers had been infected by computer viruses.

4___________ (据说)that the computer viruses were made by a group of young men like playing tricks. They all had excellent 5_________ (教育). They created the viruses just to show their intelligence. 6___________ (这种)computer viruses is named Jerusalem Viruses. These viruses can stay in computers 7___________ (很长时间). When the time comes they will attack the computers by lowering the functions, damaging their normal programs or even getting rid of all the information..

We now come to know that Jerusalem Viruses often attack computers 8__________ (在星期五)and they are spreading to a lot of computers. Among the countries that suffered computer viruses are Britain, Switzerland, the US and some 9________ (其它的)countries. But till now how to get rid of the terrible viruses 10__________ (仍然是)a problem.

　　　　　　　　　　　　　　 (7)

　 In American high school 　1 _______(大多数) students take English, science, math and history.

　 　2 _______(在英语课堂上) , the students study grammar and read famous literature. In science class, they study biology, chemistry or physics. History is 　3 ________(更有趣) to some students because they learn about important events and places 　4 ________(在美国) . Students take 　5 ______(其它) courses, too. These are electives. Some study 　6 ________(音乐)because they feel it is more enjoyable. Some study 　7 _________(计算机科学)because they 　8 ________(认为)it is more practical.

　 　9 ______(在各自课堂上) , teachers give students exams. Some exams are more difficult than others, but a good student can always do 　10 ______(好).

　　　　　　　　　　　　　 (8)

　 One kind of vacation that many Americans enjoy is camping. Each summer 　1_____ (数百万的) Americans drive to the countryside where they find places 　2_____ (野营). The national parks, many of which are 　3 _____(在山里) , are favourite camping places. Campers enjoy the 　4 _______(新鲜空气), the lakes and the forests which they find in these parks. Campers hike, swim and fish. They can also find 　5 ______(许多种)animals and plants in the parks. Mostly campers have trailers which they drive or pull behind their cars to their campsites. Trailers are like houses 　6 ______(在轮子上). They have many conveniences which people have in their homes, 　7_______(例如)electricity and hot water. But 　8 _______(大多数) campers don’t have trailers. They camp in tents which they 　9________ (搭起)in their campsites. Campers in tents don’t have the conveniences that campers in trailers have. Tent campers enjoy 　10 _________(一种简单的生活)　 .

　　　　　　　　　　　　 (9)

　　 All big cities are quite similar. Living in a modern Asian city is not very 　1 (不同於)living in an American city. The same cannot be said about living 　2 (在农场上), however.

　　 In many parts of the world, farmers and their families live 　3 (在村庄和城镇里). In the United States, however, each farm family lives on its own fields, often beyond the sight of any neighbors. 　4 (不用) traveling from a village to the fields every morning, American farmers stay 　5 (在他们的土地上)throughout the week. They travel to the nearest town　 　6 (在星期六)for shopping or on Sundays for church. The children ride on buses to large schools which serve 　7 (所有的农场家庭) living in the area. In some areas, there are small schools serving a few farm families, and the children walk to school.

　　 　8 (当然)life keeps changing for everyone, including farmers. Today there are cars, good roads, radios, and television sets. And of course there are modern machines for farming. All of these have changed farm life.

　　 For many years, however, farming in America was often a lonely way of living. Farmers 　9 (不得不)deal with their own problems, instead of getting help from others. They 　10 (学会)to try new methods, and to trust their own ideas instead of following older ways.

　　　　　　　　　　　　　　　 (10)

A teacher from a western country visited a school in an 1_______ (东方国家). In one class, she watched sixty children as they learned 2_______ (画)a cat. The teacher drew a big ○ 3_________ (在黑板上), and sixty children copied it on their papers. The teacher drew a small ○ on the top of the first and then put two △△ on top of it. The children drew 4_________ (以同样的方式). The lesson went on until there were sixty-one cats in the classroom. Each student’s cat 5________ (看上去)exactly like the one on the board.

The visiting teacher watched the lesson and 6________ (感到惊讶). The teaching methods(ways) were very much different from the way of teaching in her country. A children’s art lesson in her own country produced a roomful of pictures, each one is quite 7_________ (不同于)the others. Why? What makes this difference in educational methods? In a classroom in any country, the teacher teaches more than art or history or language.

8__________ (在一个国家里)such as the United States or Canada, students are asked to work by themselves and find answers 9_________ (他们自己). The students are helped to learn to have their own ideas. In countries such as China and Japan, students often work together and help each other in the classroom, but the teachers teach and the students listen. The students are asked to memorize a lot. They 10__________ (必须)learn the same textbook. They do the same homework and give the same answers.　

　　　　　　　　　　 (11)

He was born in Atlanta, Georgia, on January 15,1929. He was black. He lived 　1________ (仅仅)thirty-nine years, but he became world-famous in that short time. He 　2 _______(长大) in the southeastern part of the United States. He studied at Morehouse College where he met many outstanding men whose ideas he found important and exciting. There he read the writings of Thoreau, which gave him many ideas 　3 ________(关于自由) .

　 After he graduated from Morehouse, he 　4 ______(接着) to study at the University of Pennsylvania, Harvard University, and Boston University. At Boston University, he met his wife, Coretta. 　5 ________(1954), after he got his Ph.D.degree, he became the minister of a small church 　6 _________(南方的) . There he became the leader of the black people, who were poor and without power. He gave speeches and led marches. For his ideas and actions, he went to jail 　7 ____(一段时间).

　 　8 _______(许多年以后), in Washington, D.C., he spoke to a crowd of 250,000 people. He told them, “I have a dream.” That speech is still 　9 ______(著名). In 1964 he won the Nobel Peace Prize. His work was not 　10______(结束) when he died on April 4, 1968. Who was he? He was Martin Luther King.

　　　　　　　　　　　　　 (12)

Dear Mr. Costa,

I’m sorry it has taken me so long to write. I’ve been very busy with work and school, but I’ve 　1 ________(想起)you often.

How’ve you been lately? Did you have a good Christmas and New Year’s? Mac says you’ve been working hard at the restaurant and that business is very good. What 　2 _______(别的) have you been doing?

I had a short but good vacation. Mac and I went to Chicago for 　3_______ (几天)before Christmas, but I 　4 ______(不得不) come back and work between Christmas and New Year’s (including Christmas Day and New Year’s Eve)! 　5 _____(每次)something like that 　6 _______(发生)I wonder if I really want to work in the hotel business.

The other day I was thinking about the fun we used to have 　7 ______(在我们英语课堂上). I haven’t seen many of our classmates since the course was over. 　8_____ (事实上), the only one I see very often is Tomiko. I’d really like to get in touch with Franco. Does he 　9 _______(曾经) write to you? If so, could you please send me his address?

Well, Mac and I are going skating and he 　10 ______(在等我), so I guess I’d better say goodbye now. Write as soon as you can.

　　　　　　　　　　　　　　　　　　　　　　　　　　　　　 Love,

　　　　　　　　　　　　　　　　　　　　　　　　　　　　　 Maria

[练习答案]

(1)1. around 2. get along well 3. each other 4. go on 5. miss 6. make new friends 7. Many places 8. think of 9. longer 10. yourself

(2)1. thousands of 2. famous 3. on the train 4. noise 5. what they said 6. full of 7. However 8. success 9. come out 10. A week later

(3)1. two-day 2. in many different ways 3. together 4. have a party 5. Running 6. are popular 7. favourite　 8. their 9. to paint 10. For most Americans

(4)1. has been　 2. since　 3. outside 4. two hours a day 5. going to work 6. means 7. used to 8. however　 9. more common 10. large numbers of

(5)1. looking at 2. One day 3. every morning 4. on this bench 5. come true 6. A few days later 7. To his surprise 8. moved out of 9. in that big hotel 10. at all

(6)1. look for 2. At the same moment 3. found out 4. It is said 5. education 6. This kind of 7. for a long time 8. on Fridays 9. other 10. remains

(7)1. most 2. In English class 3. more interesting 4. in the United States 5.other 6. music 7. computer science 8. think 9. In each class 10. well

(8)1.millions of 2. to camp 3. in the mountains 4. fresh air 5. many kinds of

6. on wheels 7. such as 8. most 9. set up 10. a very simple life

(9)1. different from 2. on farms 3. in villages or towns 4. Instead of 5. on their land 6. on Saturdays 7. all of the farm families 8. Of course 9. had to10. learned

(10)1. eastern country 2. to draw 3. on the blackboard 4. in the same way 5. looked 6. was surprised 7. different from 9. themselves 10. have to

(11)1. only 2. grew up 3. about freedom 4. went on 5. In 1954 6. in the south 7. for a short time 8. Many years later 9. famous 10. finished

(12)1.thought about 2. else 3. a few days 4. had to 5. Every time 6. happens7. in our English class 8. In fact 9. ever 10. is waiting for me本资料由《七彩教育网》 提供！

本资料由《七彩教育网》 提供！

本资料由《七彩教育网》 提供！

本资料由《七彩教育网》 提供！

11．(2009年泰安质检)如图33所示，某同学在地面上拉着一个质量为m＝30 kg的箱子匀速前进，已知箱与地面间的动摩擦因数为μ＝0.5，拉力F₁与水平面的夹角为θ＝45°，g＝10 m/s².求：

(1)绳子的拉力F₁为多少？

(2)该同学能否用比F₁小的力拉着箱子匀速前进？如果能，请求出拉力的最小值；若不能，请说明理由．

解析：(1)箱子匀速前进，属于平衡状态，合外力为零，以箱子为研究对象，进行受力分析，其受重力、地面支持力、地面摩擦力、外界拉力，以水平、竖直为坐标轴的方向建立坐标系，利用正交分解法可得F₁cos45°＝μ(mg－F₁sin45°)；F₁＝＝100N.

(2)设拉力与水平方向的夹角为θ，利用正交分解法，将水平、竖直两个方向的平衡方程整理有

Fcosθ＝μ(mg－Fsinθ)；F＝

当θ＝arctanμ时，F有最小值，其值为

F_min＝＝60 N

答案：(1)100N　(2)能　F_min＝60 N

10．如图31所示，重力为500 N的人通过跨过定滑轮的轻绳牵引重200 N的物体，当绳与水平面成60°角时，物体静止，不计滑轮与绳的摩擦，求地面对人的支持力和摩擦力．

解析：人和重物静止，所受合力皆为零，对物体分析可得，绳拉力F等于物重200 N；人受四个力作用，将绳的拉力分解如图32所示．

图32

水平分力F_x＝F·cos60°

＝200× N＝100 N

竖直分力F_y＝F·sin60°

＝200× N＝100 N

在x轴上f与F_x二力平衡

所以静摩擦力f＝F_x＝100 N

在y轴上，三力平衡得

地面对人的支持力N＝G－F_y＝(500－100) N＝326.8 N

答案：326.8 N　100 N

图33

9．如图29所示，两滑块放在光滑的水平面上，中间用一细线相连，轻杆OA、OB搁在滑块上，且可绕铰链O自由转动，

图29

两杆长度相等，夹角为θ，当竖直向下的力F作用在铰链上时，滑块间细线的张力为多大？

解析：根据力F作用O点，产生的效果，可把力F分解为沿OA、OB的力F₁、F₂，如图32甲由对称性可知F₁＝F₂＝.

对A物体受力分析如图30乙所示．

图30

由平衡条件得：

F_T＝F₁·sin＝tan.

答案：tan

图31

8．如图27所示，一小球在纸面内来回振动，当绳OA和OB拉力相等时，摆线与竖直方向的夹角α为(　)

A．15°　 　　　　　　　　　　　　　　　　　　　　　　　　　 B．30°

C．45°　 　　　　　　　　　　　　　　　　　　　　　　　　　 D．60°

解析：对O点进行受力分析，O点受到OA绳和OB绳的拉力F_A和F_B及小球通过绳子对O点的拉力F三个力的作用，

图28

在这三个力的作用下O点处于平衡状态，由“等值、反向”原理得，F_A和F_B的合力F_合与F是等值反向的，由平行四边形定则，作出F_A和F_B的合力F_合，如图28所示，由图可知α＝15°，故答案是A.

答案：A