So, Lewis structures are really a model for a way to think about what the valence electron configuration is, and as I said, it's not based on quantum mechanics, it's something that Lewis observed far, far before quantum mechanics were discovered.

路易斯结构实际上是一个用来考虑价,电子排布的模型，而就像我说的，它并不以量子力学为基础，而是路易斯在以前发现的,在量子力学出现很早前。

麻省理工公开课 - 化学原理课程节选

Another example is when you're talking about what's been said by somebody else,

另一个例子是当你在谈论其他人曾说过的事情时，

That's what课堂 - SpeakingMax英语口语达人