tortoises
n. [脊椎]乌龟（tortoise 的复数）
例句
Tortoises have hard shells.
乌龟有坚硬的壳。
Both these fossils were dry-land tortoises.
这两块化石都是旱地陆龟。
Tortoises therefore represent a remarkable double return.
因此，乌龟是曾经往返于陆地和水中生存的代表性物种。
