When I open the blue book, the Yale guideline, the Yale catalog, it's got a page, as you all know, where it says what letter grades mean at Yale.

我打开那本蓝皮书，耶鲁指导手册，耶鲁目录，有这么一页，都见过，讲耶鲁每个评分字母表示什么。

耶鲁公开课 - 死亡课程节选

So usually the guideline is anywhere usually around 18%.

通常来说，小费的标准是在18%左右。

一定要给小费 - SpeakingMax英语口语达人

That's pretty much the guideline.

这个标准是不错的。

一定要给小费 - SpeakingMax英语口语达人