1·The Mariner spacecraft found that the surface of Mars, as well as that of its two moons, is pitted with impact craters formed by meteoroids falling in from space.
水手号宇宙飞船发现火星表面，还有它的两个卫星表面，都有由太空坠落的流星体造成的陨石坑。
2·The Sun is the hub of a huge rotating system consisting of nine planets, their satellites, and numerous small bodies, including asteroids, comets, and meteoroids.
太阳是一个巨大的旋转系统的中心，这个旋转系统由九大行星、它们的卫星和无数的小天体组成，包括小行星、彗星和流星体。
3·If a batch of meteoroids comes from the same comet, the meteor shower is formed.
如果一批流星体来自同一颗彗星，形成的就是流星雨。
4·Meteoroids are small chunks of stone or stone and iron, some of which are fragments of asteroids or comets.
流星体是小的石块或者石头和铁、其中有一些是小行星或者彗星的碎片。