1·Roids are, for the most part anyway, they are just smaller bits of asteroids and comets.
在很大程度上，Roids 只是小行星和彗星的小碎片。
2·So to talk about where meteorites come from, we need to talk about comets and asteroids.
那么讲到流星体从何而来，我们就需要讨论下彗星和小行星。
3·The solar system also has two analogous classes of objects, smaller than planets—namely, asteroids and comets.
太阳系也有两类类似的物体，比行星还小——即小行星和彗星。
4·These asteroids are like the terrestrial planets, in that they're composed mostly of rocky material and metals.
这些小行星像类地行星一样，主要由岩石物质和金属构成。
5·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。