精选优质文档-倾情为你奉上话题阅读滚动练(七)话题：自然与地理、周围的事物.完形填空。先通读下面短文，掌握其大意，然后从短文后面各题所给的选项中选出最佳选项。The water and the land are thought of as part of the earths surface.The air is _1_ thought of as a kind of blanket(毯子) _2_ the earth.But it is _3_ than that.Maybe you have been in a cave _4_ in the earth.Did you think about the air that was in the cave? The land has some air mixed in it.Air is even mixed _5_ the water in the sea.These examples sh
