Optimality
[计] 最佳性
🗣️ 情景例句
OK. Good night.
好， 晚安。
Necessity and opportunity may make a coward valiant.
需要和机会，可使懦夫变勇敢。
We're going to leave at about seven thirty next Monday morning.
我们打算下星期一早上7：30 左右出发。