And, I will go through the actual line by line derivation not because I want to do derivations in class.

我们要仔细讨论实际的线,和推导出来的线,并不是我想在这节课做推导。

麻省理工公开课 - 固态化学导论课程节选

And, a lot of the derivations you will see in physics rely on this being able to model as point charges.

然后，你在物理学中看到的许多东西,都是靠以点电荷为模型得到的。

麻省理工公开课 - 固态化学导论课程节选

I've been teaching long enough to know that doing derivations in class is equivalent to pouring ice water on the proceedings, so I do this sparingly.

我已经教了这么长时间书,所以我知道在课堂上讲推导,就好像泼冰水一样，所以我在讲这个的时候很小心。

麻省理工公开课 - 固态化学导论课程节选

It is not because I favor derivations in class.

而不是我喜欢在课堂上讲推导。

麻省理工公开课 - 固态化学导论课程节选