题目内容：
阅读下列短文,回答题.There are some objects in the sky that move so quickly that sometimes you only see them outof the comer of your eye.These are some of the huge number of bits of rock and dust that are floating around in space, called meteoroids.Normally, we cannot see them at all, but if they travel tooclose to the Earth, they get caught by the pull of the Earth, and begin to fall towards us.They fallfaster and faster, until they hit our atmosphere (大气层), by which time they are going so fast thatthey begin to bum up, and all that you see is a flash of light that moves very quickly across the skyand disappears.These shooting stars, or meteors as they are properly called, are quite common,and sometimes you may see several in a night.
Most meteoroids are very small bits indeed, and they bum up long before they get to theEarth.However, a very few do manage to get all the way through the atmosphere, and actually fallto the ground.usually they do not do much damage, although this is not always the case.
Meteoroids that actually manage to reach the Earth are called meteorites.Most countries haveplaces where meteorites have struck the Earth.some of these places are very large indeed and aretourist attractions.
Why do some objects from outer space fall to the ground? A．They are too big.
B．They are hit by huge rocks.
C．They move too fast.
D．They are pulled by the Earth.
参考答案：
答案解析：