题目

风洞是对飞机、导弹性能进行检测的一种高科技产物，现代汽车的生产也有运用风洞技术进行检测的，如图所示是小丽所在兴趣小组设计的一个类似于风洞的实验装置，他们在桌面上放有许多大小不同的塑料球，这些塑料球的密度均为，用水平向左恒定的风作用在球上，使它们做匀加速运动（摩擦不计）。已知风对球的作用力F与球的最大横截面积S成正比，即F=kS，走为一常量。对塑料球来说，可以认为空间存在一个风力场，在该风力场中风力对球做功阅读理解。    As we all know, the Moon is the moon (卫星) of Earth, and it goes around the earth. Scientists have already known a lot about it, (A) but they've always wanted to know more about it. And they decided to send men to the Moon. They think it's the best way to learn more about the moon.    But how do the astronauts (宇航员) get to the moon? The moon is about 384,000 kilometres away from theearth. They can't take a plane to the Moon. But something can fly even when there is no air. That is a mannedspacecraft (载人宇宙飞船). Several astronauts have been to the Moon in the manned spacecraft. 1. "it" in sentence A refers to (指得是) _____. [     ] A. the planets B. the Moon C. the sky D. the star 2. The Moon is _____ away from the earth. [     ]A. over 384,000 kilometers B. only 384,000 kilometers C. about 384,000 kilometers D. about 348,000 kilometers 3. The best way to learn more about the Moon is to _____. [     ]A. send men there B. take photos of it C. live on it D. find another moon 4. The astronauts have been to the moon in the _____. [     ]A. plane B. manned spacecraft C. space station D. air 5. The best title (题目) for this passage is _____. [     ]A. The Moon B. The exploration (探索) of the Moon C. Men to the MoonD. The manned spacecraft