Keystones
n. 重点( keystone的复数形式 ); 要旨; 基本原理; 拱心石
🗣️ 情景例句
Let us try it!
让我们试试吧！
A bird is known by its note,and a man by his talk.
鸟以声闻，人以言知。
Jim ! Jim ! It's time to get up !
吉姆，吉姆，该起床了！