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【单选题】
Unless we spend money to spot and pr asteroids(小行星) now, one might crash into Earth and destroy life as we know it, say some scientists. 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.
A.
Asteroids are bigger versions of the meteoroids(流星) that reace 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.
B.
Buy $ 50 million worth of now 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.
C.
Some scientists favor pushing asteroids off course with nuclear weapons. But the cost wouldn’t be cheap.
D.
Is it worth it Two things experts consider when judging any risk are: 1) How likely the is; and 2) How bad the consequences if the 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 ."
E.
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) rocks than from a great nuclear fleet set against them," said a New York Times article.
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【单选题】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...
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.
【单选题】2011年7月，天文学家发现了一颗直径300米的小行星，它与地球有着相同的公转轨道，并始终在地球前方“打转”。这一发现再次印证了( ) ①自然界是物质的 ②人的意识是物质世界的产物 ③人类社会是物质的 ④世界真正的统一性在于它的物质性
A.
①②
B.
③④
C.
②③
D.
①④