For more than twenty years scientists have been searching for signs of life on other planets. Most of these searches have been done over the radio. The hope is that someone in outer space may be trying to et in touch with us. Scientists also have sent radio and television messages on space-ships traveling through space, on the chance that someone may be receptive to such messages.

　 Scientists are using powerful radio telescopes to listen to signals from about 1,000 stars, all within 100 light years of earth. In addition, they will scan(扫视)the entire sky to “listen” to radio messages from more distant stars. Using a computer, they will be able to monitor more than eight channels at one time. Scientists are looking for any signal that stand out from the background noise.

　 Of the 200 billion stars in the Milky Way galaxy (银河系), scientists find that five percent are like our sun. Perhaps half of them have a planet earth. Such a planet would be a reasonable distance from the star for temperatures to be right for the evolution(进化)of life. Based on the inhabitable(that can be lived in)planets in our galaxy, most scientists agree tat chances are likely that one or more of these planets support some life.

　 However, many scientists wonder whether intelligent(有智力的)life exists on other planets. Some believe that twenty years of searching without any intelligible messages shows that no one is out there. They say that the evolution of intelligence comparable to ours is unlikely.

　 Other scientists believe that our search hasn’t been long enough to rule out the possibility that intelligent life exists in our galaxy. Although our sun family is only about five billion years old, our galaxy is about 20 billion years old. In that time, some scientists think it is likely that civilization(文明)much more advanced than ours have developed. Perhaps these civilizations send us no signals; perhaps we have not recognized the signals they have sent us. If we hope to find intelligent life, these scientists believe that we have to keep looking.

1. According to the passage, how many planets in our galaxy might be inhabitable?

　 A. 5 billion.　　 B. 10 billion.　　　 C. 15 billion.　　　 D. 200 billion.

2. The first paragraph in this passage is mainly about ____.

　 A. how scientists are looking for signs of life on other planets

　 B. why scientists are looking for signs of life on other planets

　 C. where scientists are looking for signs of life on other planets

　 D. when scientists are looking for signs of life on other planets

3. The underlined word “monitor” in the passage means ____.

　 A. find　　　　　 B. follow　　　　 C. check　　　　 D. form

Our school doesn’t ____ students’ staying in the classroom too long. We think they should have time for sports.

A. advocate　 B. admit　　 C. assess D. approach

It is said that the female thief they caught was fined five times　　 that she should have paid.

A.the amount of money　　 B.as more money as　　　

C.much money than　　 　 D.as much money than

_____ all over the hills and around the lake are wild flowers of different kinds.
  A. To grow      B. Growing     C. grown      D. Grow  

The coach asked his staff to　　　 the large group of journalists waiting for him to announce his training plans.

A. adapt to　 　　　 B. attend to 　　 C. refer to　 　　 D. appeal to

If you ____________ stop smoking, you can only expect to have a bad cough.

A. won’t　　　　 B. would not　 C. do not　　 D. can not

My father did not go to New York; the doctor suggested that he ___ there.

A. not went B. won't go C. not go D. not to go

— ______ I stay with you?

　 —Well, I would rather you　　　　　 me alone for a while.

　 A．Will; leave　 B．Shall; leave　 C．Will; left D．Shall; left

She devoted herself ____ to her research and it earned her a good reputation in her field.

　 A. strongly　　　 B. extremely　　　　　　 C. entirely　　　　 D. freely

______the fire broke out, three fire-engines were rushed to the spot.

A. Hardly B. Quickly　 C. Immediately　 D. Gradually