一个密切有关的概念是自由价。

A closely related concept is that of free valence.

youdao

另一个与成本有关的概念是经验曲线。

The second cost-related concept is the experience curve.

youdao

有几个人曾问我有关极性概念的由来，极性概念是我去年开始研究的。

Several people have asked me about the origins of the polarity concept I began exploring last year.

youdao

Today what I want to do is give you some sense of this body of writing.

今天我想做的是给你们灌输一些有关这种写作文体的概念。

耶鲁公开课 - 现代诗歌课程节选