But if you say, well, I don't know how to do this, I am not going to bother, don't grade the paper.

但是如果你说，好吧，我不知道怎么做这个，我想麻烦，别给试卷评分。

麻省理工公开课 - 固态化学导论课程节选

and your hairstylist says, "Oh, I know exactly what to do. We should make your hair blonde."

你的发型师说，“哦，我知道该怎么做。我们要把你染成一头金发。”

I'm afraid of 课堂 - SpeakingMax英语口语达人