2000年1月大学英语四级考试试题及答案 |
2006-2-17 1:13:19 点击数： 进入论坛 |
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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 acros s the night sky.Most orbit the sun far from Earth and don"t threaten us.But th ere are also thousads 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; and 2) How bad the consequences if the event occurs.Experts think an asteroid big enough to destroy lots of life might strike Earth once eve ry 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.
21. 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) There are more asteroids than meteoroids.
D) Asteroids are more mysterious than meteoroids.
22. What do scientists say about the collision of an asteroid with Earth?
A) It is very unlikely but the danger exists.
B) Such a collision might occur once every 25 years.
C) Collisions of smaller asteroids with Earth occur more often than expected.
D) It"s still too early to say whether such a collision might occur..
23. 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.
24. 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 |
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| 2007年4月大考时间 |
| 2007年4月21日-4月22日 |
| 2007年7月加考时间 |
| 2007年7月7日-7月8日 |
| 2007年10月大考时间 |
| 2007年10月27日-10月28日 |
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