Question

Unless we spend money spotting and preventing asteroids(小行星)now, one might crash into Early 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 is 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 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 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(世界末日)rocks than from a great nuclear fleet set against it,”said a New York Times article． (1) 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． (2) 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． (3) 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． (4) 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 unlike to happen in our lifetime． D． workable solutions still have to be found to prevent a collision of asteroids with Earth

Answer 1

答案：1．B;2．A;3．B;4．D;
解析：

(1)	文章第二段第一句指出，小行星是比划过夜空的流星大的天体。可见二者是性质相同的天体，只是大小不同。
(2)	文章第二段后两句指出，绝大多数的小行星围绕太阳运行。远离地球，不会威胁到我们。但仍然有上千颗小行星可能撞击地球。可见，小行星与地球相撞的可能性很小，但危险确实存在。B项为概念错误。文章第三段指出，确定大多数小行星的位置需要25年。文章第五段又提到，大到足以有很强毁灭性的小行星可能每五十万年与地球碰撞一次，可见B项是错误的，C项文中没有提到，D项与文章内容不符。
(3)	注意最后一段第一句中，“cure”指解决办法，即用核武器改变小行星的运行轨道，而“disease”指小行星可能与地球碰撞这件事情。由此本句可理解为核武器会比小行星带来更糟的后果，并且带给人们更大的恐慌。故选B项。
(4)	应依据全文内容作出选择。全文一再强调小行星与地球碰撞的危险性，但没有提及在不久的将来会发生，故排除B项。文章最后提出对付小行星的核武器在改变小行星运行轨道的同时会毁灭地球，那么可以得出结论：解决小行星撞击地球的可行的办法有待进一步的探索。A项是事实，而不是结论。