So, if you by chance, I know it's very rare, but if by chance you don't get the class you can always follow up later.

如果你们偶然，我知道不太可能，但是如果不小心你们错过了某节课,你们就可以在之后补回来了。

麻省理工公开课 - 固态化学导论课程节选

So sometimes, if you miss a class, you can just kind of check in earlier years, like lectures,

所以有时候，如果你错过了一节课，你可以看看前几年的讲座，

开放式的课程？ - SpeakingMax英语口语达人