So, you already have a hint that methyl groups are never in the middle, they always have to be on the outside.

那么，你已经得到了一个提示,那就是甲基永远都不可能在中间，它们总是在外侧。

麻省理工公开课 - 化学原理课程节选

C H 3 So any time you see c h 3 here, remember that that's methyl and that's going to be a terminal group.

因此一旦你看到，记得这就是甲基,而且只能在结构的末端。

麻省理工公开课 - 化学原理课程节选

Any time you see a c h 3, this means a methyl group.

一旦你看到一个，C，H，3，的组合，这就意味着一个甲基。

麻省理工公开课 - 化学原理课程节选