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

We can make some substitutions here using some of the derivation on the previous board which will give us the Planck constant divided by 2 pi mass of the electron times the Bohr radius.

在这里我们也可以,用我以前在黑板上写过的一些词来取代它,得到的是普朗克常数除以2π电子质量,再乘以波尔半径。

麻省理工公开课 - 固态化学导论课程节选

I will try to finish every lecture on time, but sometimes if I'm in the middle of a sentence or the middle of a derivation, I may have to go over by a couple of minutes; there's no need to shuffle your feet and move stuff around.

我会尽量准时下课的,但是有时候如果我正在讲解一个概念,或者正在推导一个公式,我会稍微多讲几分钟,你们不用来回蹭脚,收拾东西什么的

耶鲁公开课 - 基础物理课程节选