C
The journey to the moon had been the first step toward future exploration(探险) in space. The distance between the Moon and Earth is very short indeed when compared with the distances between Earth and the other planets. Mars, the nearest planet to Earth is millions of miles away. Traveling to the planets will be man’s next aim. Such travels will be more challenging than the trip to the moon and certainly more adventurous.
    Recently, two American spaceships, Vikings 1 and 2, landed on Mars trying to discover whether that planet has any life on it. So far the signs of life on Mars has neither confirmed(确认) nor ruled out. Russians have discovered that the surface of Venus(金星) is so hot that it is almost certain that there is no life there. Also the atmosphere of Venus is extremely dense(稠) and the pressure is nearly a hundred times greater than that of the Earth’s atmosphere.
    Scientists believe man may find planets which have the same conditions as those we have on Earth , but man should realize Earth will be his only home for a long time and begin to love and care for it.
9. According to the passage, traveling to the planets will be ________.
  A. much easier and even more interesting
  B. far more exciting and dangerous
  C. man’s final aim                  D. man’s first step
10. Which of the following is Not true?
  A. Mars is nearer to the earth than the moon.
  B. The moon is much nearer to the earth than Mars.
  C. Of all the planets, Mars is the nearest to the earth.
  D. All the planets are much farther to the earth.
11. From the passage, we can guess_____.
  A. there is life on Mars        B. there is no life on Mars
  C. the atmosphere of Mars is not so dense as that of Venus
  D. scientists will have little hope to find the answers
12. Man can live on under the conditions of _______.
  A much too hot surface          B. the same pressure as we get on earth
  C. normal atmosphere as we have on earth       D. both B and C
D
    Unless we spend money to spot and prevent asteroids(小行星) now, one might crash into Earth and destroy life as we know it , say some scientists.
    Asteroids are bigger versions of the meteoroids(流星) that race across the night sky. Most orbit the sun far from Earth and don’t threaten us. But there are also thousands of asteroids whose orbits put them on a collision course with Earth.
    Buy $ 50 million worth of new telescopes right now, Then spend $ 10 million a year for the next 25 years to locate most of the space rocks. By the time we spot a fatal one, the scientists say , we’ll have a way to change its course.
    Some scientists favor pushing asteroids off course with nuclear weapons. But the cost wouldn’t be cheap.
    Is it worth it? Two things experts consider when judging any risk are: 1) How likely the event is; 2) How bad the consequences if the event occurs. Experts think an asteroid big enough to destroy lots of life might strike Earth once every 500 000 years. Sounds pretty rare-but if one did fall, it would be the end of the world. “ If we don’t take care of these big asteroids, they’ll take care of us,” says one scientist. “ It’s that simple.”
    The cure, though , might be worse than the disease. Do we really want fleets of nuclear weapons sitting around on Earth? “The world has less to fear from doomsday(毁灭性的) rocks than from a great nuclear fleet set against them,” said a New York Times article.
13. What does the passage say about asteroids and meteoroids? _________.
A. They are heavenly bodies different in composition
B. They are heavenly bodies similar in nature
C. These are more asteroids than meteoroids
D. Asteroids are more mysterious than meteoroids
14. What do scientists say about the collision of an asteroid with Earth? _______.
A It is unlikely but the danger exists
B. Such a collision might occur once every 25 years
C. Collision of smaller asteroids with Earth occur more often than expected
D. It’s still too early to say whether such a collision might occur
15. What do people think of the suggestion of using nuclear weapons to alter the course of asteroids? _______.
   A. It sounds practical but it may not solve the problem
   B. It may create more problems than it might solve
   C. It is a waste of money because a collision of asteroids with Earth is very unlikely
   D. Further research should be done before it is proved applicable
16. We can conclude from the passage that________.
   A. while pushing asteroids off course nuclear weapons would destroy the world
   B. asteroids racing across the night sky are likely to hit Earth in the near future
   C. the worry about asteroids can be left to future generations since it is unlikely to happen in our lifetime
   D. workable solutions still have to be found to prevent a collision of asteroids with Earth

III．单句改错
1. Measures should be taken to stop the river from being polluting.
2. The gardener explained us the development of a seed into a plant.
3. The audience exploded laughter while listening to the cross talk.
4. The strength of the explosion broke all the windows in the building.
5. A violence storm struck our town and caused serious damage yesterday.
6. The bird was lucky enough to escape from fired.
7. Having learnt the text, we know many more about gravity.
8. Some animals produce their young from their bodies.
9. He seems that he has worked in sales for several years.
10. Languages have developed for a long period of time.
IV．句子翻译
1．当SARS爆发时，突然的恐惧迅速地弥漫全国。(break out)

2. 只要更努力，你终久会成功。(in time)

3．他们尽力使那些遭遇地震不幸的人们高兴起来。( cheer up)

4．我们应该想办法防止有害气体的蔓延。(prevent… from)

5．她发现河面上有奇怪的东西浮着，这使她感到非常害怕。(float )

6．运动员没有听从教练员的指令，结果使他打赢比赛的计划落空。（disappoint）

7．随后它会变成什么曾经是一个迷, 直到最后这团尘埃开始慢慢地合成一个环绕太阳运转的球状物。（combine into ）

8．在未来的千百万年中, 生命能否在地球上延续将取决于这个问题能否得到解决。

9．有些奇怪的动物会生蛋，但又给它的幼崽喂奶。(lay eggs)

10．当对他们有害的动物消失时，哺乳动物便快速繁殖。(multiply)

必修4　Unit 4 Astronomy: the science of the stars答案
第一部分：基础练习
I．词汇
1．选词填空
1. spread   2.disappointed    3. floated,   4. published, publishing    5.force 
6. violently  7. solid         8. exploded   9. development         10. surface
2．词组识记
1. depend on                      2. 把……当／看作
3. now that                       4. 科学地研究这门学科
5. fall over                       6. 生命的起源
7. explain sth to sb                 8. 使生命有可能进化
9. with time passing by／going by /as time went / passed by  10. 阻止某人做某事
11. look forward to                 12. 地球唯一的自然卫星
13. lead to / result in                14. 慢慢升空
15. hold one’s breath                16. 做笔记
17. make a trip to space              18. 对……知之甚多
19. break out                       20. 找到了它的窍门
II．语法
a. 1.what, that 2. Whoever 3.that 4. How, what 5.That
6.which 7.Whichever 8.Why 9.Where ／How 10.Who
b. 1.What is needed for the space trip
 2.who will come out first / take / get the first place
 3. That Yang Liwei landed on the earth safe from space
 4. when he joined the Party
 5. How astronauts eat, sleep and walk in space
 6.Where the earth is different from / differs from other planets
 7. Why he suddenly changed his mind
 8. When war will disappear from the world
 9. What satisfied us most / What made us most satisfied / What was most satisfying
10. How we can improve our studies
III．单项填空
ACDBA       AABCC        CAACD
第二部分：综合练习
I．完形填空
BBDCC      DADDD      ABDAC      CDBCD
 II．阅读理解
CDBB      ACDC       BACD       BABD
III．单句改错
1. polluting → polluted      2. explained us → explained to us
3. exploded laughter → exploded into laughter  4. strength → force
5.violence → violent    6. from fired → from being fired
7. many → much       8. from their bodies → from within their bodies
9. He → It            10. for → over
IV．句子翻译
1. When SARS broke out, a sudden fear spread out quickly all over the country.
2. Try harder, and you can succeed in time.
3. They tried their best to cheer up those unfortunate people suffering from the earthquake.
4. We should find some ways to prevent the harmful gas from spreading.
5. She found something unusual floating on the surface of the river, which quite frightened her.
6. The players didn't follow the director's instructions and disappointed his plan to win the game/ which disappointed his plan to win the game.
7. What it was to become was a mystery until the dust began to slowly combine into a ball moving around the sun.
8. Whether life will continue on the earth for millions of years to come will depend on whether this problem can be solved.
9. Some strange animals lay eggs but feed their young on their milk.
10. The mammals multiplied fast when the animals, harmful to them, disappeared.

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