This is a portfolio, which has all oil and stocks and it has no bonds.

这个投资组合，包括有石油，股票，没有债券。

耶鲁公开课 - 金融市场课程节选

One thing that I want to mention that is really important is once you have double bonds, what happens between those two atoms in the molecule is they can no longer rotate in relation to each other.

我要提醒你们的非常重要的一点事,一旦有了双键，分子中的两个原子,就不能相对旋转了。

麻省理工公开课 - 化学原理课程节选