adj.地球的,土地的;
例句:
The spacecraft burned up when it re-entered the earth's atmosphere.
宇宙飞船重新进入地球大气层时烧毁了.
The lunar stone is different from earth's.
月球的石头和地球的不同.
This book is about the earth's magnetism.
这本书是有关于地磁的.