All right, so let's think of a more complicated example of having a double bond, and maybe a more interesting example, and this is talking about benzene.

好了，让我们来看关于双键的,一个更复杂的例子，也许是更有趣的例子，我们要讨论苯环。

麻省理工公开课 - 化学原理课程节选

but I think I'm going to be, um, I'm double concentrating in economics and religious studies.

不过我想我该做出选择了，目前我在学习的是经济和宗教方面的内容。

想学习宗教学 - SpeakingMax英语口语达人

So let's think about how we can classify single and double and triple bonds, which is what we're really used to dealing with in terms of these sigma bonds and these pi bonds.

让我们想想怎么来分类单键双键,和三键，这在我们在考虑sigma键,和π键是很有用的。

麻省理工公开课 - 化学原理课程节选