Are you a social butterfly, or do you prefer being at the edge of a group of friends? Either way, your genes and evolution may play a major  1  , US researchers reported on Monday.

While it may come as no surprise that genes may help explain  2  some people have many friends and others have  3  , the researchers said, their findings go just a little farther than that.

"Some of the things we find are  4    uncommon," said Nicholas Christakis of Harvard University in Massachusetts, who helped   5  the study.

"We find that how interconnected your friends are   6   on your genes. Some people have four friends who know each other and some people have four friends who don't  7  each other.  8     Dick and Harry know each other depends on Tom's  9    ," Christakis said in a telephone interview.

Christakis and colleague James Fowler of the University of California San Diego are  10     known for their studies that show obesity, smoking and happiness spread in networks.

For this study, they and Christopher Dawes of UCSD used national data that   11   more than 1,000 identical(同卵的) and fraternal（異卵的） twins’ genes. Because  12  share an environment, these studies are good for showing the impact that genes have  13  various things, because identical twins  14  all their genes while fraternal twins share just half.

"We found there appears to be a genetic tendency to introduce your friends  15  each other," Christakis said.

There could be good, evolutionary reasons  16  this. People in the middle of a social network could be secret to useful gossip,  17   the location of food or good investment choices.

But they would also be at risk of catching effects from all sides -- in which case the advantage would  18   more cautious social behavior, they wrote in the Proceedings of the National Academy of Sciences.

"It may be that natural selection is  19  not just things like whether or not we can resist the common cold, but also who it is that we are going to come into  20   with," Fowler said in a statement.

(    ) 1. A. role                 B. rule           C. roll                  D. pole

(    ) 2. A. where                  B. why          C. when               D. how

(    ) 3. A. a few                      B. several      C. few                  D. some

(    ) 4. A. generally          B. mainly      C. mostly              D. frankly

(    ) 5. A. conduct            B. introduce   C. conflict            D. instruct

(    ) 6. A. depends            B. bases        C. take                 D. put

(    ) 7. A. see                   B. inspect      C. learn               D. know

(    ) 8. A. When                   B. Where       C. What               D. Whether

(    ) 9. A. genes                      B. brains        C. appearances      D. figures

(    ) 10. A. much             B. best           C. very                 D. least

(    ) 11. A. recorded        B. illustrated C. described          D. compared

(    ) 12. A. brothers          B. sisters        C. twins               D. cousins

(    ) 13. A. with                      B. on             C. for                   D. to

(    ) 14. A. share              B. have          C. own                 D. show

(    ) 15. A. into               B. to             C. in                    D. from

(    ) 16. A. for                 B. with          C. to                    D. at

(    ) 17. A. in addition to B. due to       C. as for                      D. such as

(    ) 18. A. lie on             B. bring in     C. lie in               D. send in

(    ) 19. A. acting on               B. putting on C. relying on        D. sending on

(    ) 20. A. contract          B. face          C. join                  D. contact

There are about fifteen hundred languages in the world.But ___1___ a few of them are very ___2___. English is one of these. Many, many people use it, not only in England and the U. S. A, but in other parts of the world. About 200, 000, 000 speak it as their own language. It is difficult to say how many people are learning it as a ___3___ language. Many millions are ___4___ to do so.

Is it easy or difficult to learn English? Different people may have different ___5___. Have you ever ___6___ the ads of this kind in the newspapers or magazines?

“Learn English in six month, or your ___7___ back ...” “Easy and funny? Our records and tapes ___8___ you master your English in a month. ___9___ the first day your ___10___ will be excellent. Just send ...” Of course, it never ___11___ quite like this.

The only language that seems easy to learn is the mother tongue. We should ___12___ that we all learned our own language well when we were ___13___. If we could learn English in the same way, it would not seem so difficult. ___14___ what a small child does. He listens to what people say. He tries what he hears. When he is using the language, talking in it, and ___15___ in it all the time, just imagine how much ___16___ that gets!

So it is ___17___ to say that learning English is easy, because a good command of English ___18___ upon a lot of practice. And practice needs great effort and ___19___ much time. Good teachers, records, tapes, books, and dictionaries will ___20___. But they cannot do the student’s work for him.

1. A. not           B. quite          C. only           D. very

2. A. difficult       B. important      C. necessary      D. easy

3. A. native          B. foreign         C. useful        D. mother

4. A. learning       B. enjoying        C. trying         D. liking

5. A. questions            B. problems      C. ideas          D. answers

6. A. found          B. watched       C. noticed          D. known

7. A. knowledge     B. time          C. money              D. English

8. A. make           B. help           C. let              D. allow

9. A. From           B. On            C. Since         D. After

10. A. spelling      B. grammar       C. English          D. pronunciation

11. A. happened      B. know               C. seemed         D. felt

12. A. know        B. remember       C. understand    D. think

13. A. students           B. children          C. babies        D. grown-ups

14. A. Imagine           B. Mind           C. Do             D. Think of

15. A. using       B. thinking     C. trying         D. practicing

16. A. time         B. money          C. language        D. practice

17. A. hard        B. easy              C. funny         D. silly

18. A. depends     B. tries            C. has            D. takes

19. A. uses        B. takes             C. gets           D. costs

20. A. do         B. work            C. help           D. master

　Many people believe the glare（炫目的光）from snow causes snowblindness. Yet, with dark glasses or not, they find themselves suffering from headaches and watering eyes, and even snowblindness ,when exposed to several hours of“ snow light”.

　　The United States army has now determined that glare from snow does not cause snowblindness in troops in a snow -covered country. Rather ,a man’s eyes frequently find nothing to focus on （聚集） in a broad space of snow- covered without- grass land. So his gaze continually moves and jumps back and forth over the entire landscape in search of something to look at. Finding something, hour after hour, the eyes never stop searching and the eyeballs become tired and the eye muscles ache. Nature makes up for this discomfort by producing more and more fluid （流 體） which covers the eyeball. The fluid covers the eyeball in increasing quantity until it makes eyes difficult to see dearly, and the result is total, even though for a short time, snowblindness.

　　Experiments led the Army to a simple method of overcoming this problem. Scouts（偵察兵）ahead of the troops are trained to shake snow from evergreen bushes, creating a dotted line as they cross completely snow - covered landscape. Even the scouts themselves throw lightweight, dark - colored objects ahead on which they can focus too. The men following can then see something. Their gaze is arrested. Their eyes focus on a bush and having found something to see, stop searching the snow -blanketed landscape. By focusing their attention on one object at a time. the men can cross the snow without becoming hopelessly snowblind or lost. In this way the problem of crossing a continuous white land is overcome.

To prevent snowblindness caused by the strong light from snow, wearing glasses or not ________.

　　A. depends on whether the snow is white enough

　　B. makes no difference

　　C. makes much difference

　　D. depends on whether the snow is thick

When the eyes are tired, tears flow out ________.

　　A. to clear the vision

　　B. to make the eyes stop searching

　　C. to make the vision unclear

　　D. to produce more and more liquid

Snowblindness can be avoided ________.

　　A. by moving one’s gaze back and forth

　　B. by walking ahead and keeping looking around

　　C. by making up for the discomfort of one’s eyes

　　D. by providing the eyes with something to focus on

There are about fifteen hundred languages in the world.

But ___1___ a few of them are very ___2___. English is one of these. Many, many people use it, not only in England and the U. S. A, but in other parts of the world. About 200, 000, 000 speak it as their own language. It is difficult to say how many people are learning it as a ___3___ language. Many millions are ___4___ to do so.

Is it easy or difficult to learn English? Different people may have different ___5___. Have you ever ___6___ the ads of this kind in the newspapers or magazines?

“Learn English in six month, or your ___7___ back ...” “Easy and funny? Our records and tapes ___8___ you master your English in a month. ___9___ the first day your ___10___ will be excellent. Just send ...” Of course, it never ___11___ quite like this.

The only language that seems easy to learn is the mother tongue. We should ___12___ that we all learned our own language well when we were ___13___. If we could learn English in the same way, it would not seem so difficult. ___14___ what a small child does. He listens to what people say. He tries what he hears. When he is using the language, talking in it, and ___15___ in it all the time, just imagine how much ___16___ that gets!

So it is ___17___ to say that learning English is easy, because a good command of English ___18___ upon a lot of practice. And practice needs great effort and ___19___ much time. Good teachers, records, tapes, books, and dictionaries will ___20___. But they cannot do the student’s work for him.

1. A. not  B. quite   C. only    D. very

2. A. difficult  B. important   C. necessary    D. easy

3. A. native     B. foreign       C. useful D. mother

4. A. learning  B. enjoying     C. trying D. liking

5. A. questions       B. problems    C. ideas   D. answers

6. A. found     B. watched     C. noticed       D. known

7. A. knowledge     B. time    C. money       D. English

8. A. make      B. help    C. let      D. allow

9. A. From     B. On      C. Since  D. After

10. A. spelling       B. grammar    C. English      D. pronunciation

11. A. happened     B. know  C. seemed       D. felt

12. A. know    B. remember   C. understand  D. think

13. A. students       B. children     C. babies D. grown-ups

14. A. Imagine       B. Mind  C. Do      D. Think of

15. A. using    B. thinking     C. trying D. practicing

16. A. time     B. money       C. language    D. practice

17. A. hard     B. easy    C. funny  D. silly

18. A. depends       B. tries    C. has     D. takes

19. A. uses      B. takes   C. gets    D. costs

20. A. do B. work   C. help    D. master

The Ministry of Education has spared no efforts to bring on IT learning. What is its main aim? Is it to teach students how to learn the computer or is it meant to change the usual method of teaching in order to    1  students’ strong interest in computers?

Teaching students computer knowledge and skills is different     2  giving class lessons through the use of computers. And schools are beginning to pay much attention to using computers to teach students. There is     3  about the fact that IT learning plays an important role as a new teaching tool in this day of technology.    4  ,?views differ on whether the schools can achieve their targets, as success     5  whether they can make use of computers effectively.

Let’s take the subject of Chinese as an example and see    6  difficulties the experts face in their IT management. At present,20 percent of lessons are given with the help of computers. In other words, in a period of 10 weeks, a Chinese-language teacher must spend two weeks to teach the subject    7  .In carrying out such a major policy as IT learning, the experts should know the    8  that different teachers teaching different subjects have different demands, thus making it     9  to see the policy through.

Some teachers, having already got some computer knowledge, will still be forced to    10  the training courses with those who have zero knowledge about computer.

Another problem is that new teachers may be sent to work in schools    11  IT learning has just started. All teachers—including the seniors who are very     12  in teaching, but who suddenly have no idea what to do when it comes to computers will have to    13  from the very beginning. They will become    14  and their teaching performances may be badly affected. The experts have found out how much of each subject is taught by computers in every school, and have     15  all schools to complete the given work. A hard-pressed teacher may put the daily teaching     16  or the courses onto the computer just to order the required time for IT learning and then    17  the usual way. Furthermore, he may leave school work to his    18  through the computer before class comes to an end in order to “complete” his IT learning    19  .   20   the teaching of the Chinese language is concerned, do computer lessons really achieve the desire goals to raise the students’ level of Chinese, pass on common values and so on? I am not so sure.

1.A.show                      B.be                             C.match                       D.have

2.A.with                       B.to                             C.in                             D.from

3.A.no reason               B.no doubt                   C.no need                     D.no time

4.A.However                B.Therefore                  C.And                          D.So

5.A.depends on             B.leads to                            C.results in                   D.believes in

6.A.that                        B.such                          C.what                         D.how

7.A.the usual way          B.the regular way      C.the best way                     D.the new way

8.A.fact                        B.message                    C.news                         D.truth

9.A.easy                       B.helpful                      C.hard                          D.fast

10.A.sit for                   B.run for                      C.give                          D.attend

11.A.for which                  B.that                           C.where                       D.which

12.A.interested              B.satisfied                    C.successful                  D.experienced

13.A.work                    B.start                          C.teach                         D.manage

14.A.pleased                 B.disappointed              C.certain                      D.comfortable

15.A.ordered                B.improved                  C.encouraged                D.instructed

16.A.methods               B.skills                         C.programs                   D.performances

17.A.make a living        B.give lessons         C.go to lectures            D.does work

18.A.work-mates           B.headmasters         C.instructors             D.students

19.A.skills                    B.experiences                C.duties                        D.methods

20.A.As                       B.So long as                 C.Even though              D.As far as