It is no longer, in other words, that which drives the line in the story.

换句话说，它不再是引领故事发展的主线。

耶鲁公开课 - 文学理论导论课程节选

It's more obvious because there are probably fewer lines there, so that you can focus on the primary line, the basic line--the bass line.

更明显的是这里也许有几条线，所以你可以将重点放在主线上，基准线，也就是低音线。

耶鲁公开课 - 聆听音乐课程节选

That's the really important, serious line--certainly politically and in other ways as well.

这是非常重要的一条主线,政治和其他方面亦是如此

耶鲁公开课 - 古希腊历史简介课程节选

So it's really parallel to an insurance discussion.

讨论的主线与保险业是相对应的

耶鲁公开课 - 金融市场课程节选

So these names, they don't really make any sense why they're called past s p and f, and it turns out that it comes from spectroscopy terms that are pre-quantum mechanics where, for example, this is called the sharp line, I think the principle, the diffuse, and the fundamental.

看到这些名字，你会发现,它们为什么叫s，p，f是没什么道理的，事实上,它们来源于,量子力学之前的光谱学中的术语，例如，它们分别叫做锐线，我认为是主线，漫射和基本。

麻省理工公开课 - 化学原理课程节选