used to show that you have not heard or understood something

"So what do you want to do tonight?" "Huh? What did you say?" “那么今天晚上你想干什么？”“嗯？你说什么？”

Huh? These instructions don't make sense! 嗯？这些说明莫名其妙！

used to express disapproval

Huh, I don't think much of that idea! 哼，我觉得那个主意不怎么样！

used at the end of a question or statement, especially when you want someone to agree with what you have said

I'll bet you wish you hadn't done that, huh? 我敢肯定你自己也希望没干那件事，嗯？

Pretty cool, huh? 很酷，是不是？