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【单选题】
2013年7月14日凌晨1时许，已成为我国首个人造太阳系小行星的嫦娥二号卫星，与地球间距离突破（ ）万公里，再次刷新“中国高度”。
A.
5 000
B.
6 000
C.
7 000
D.
8 000
参考答案：
参考解析：
刷刷题刷刷变学霸
举一反三
【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.