你在哪个班用英语怎么说？

答案是：What class are you in?

来源：这个问题的来源是中文语言中的“你在哪个班”，在英语中表达这个意思的方式是：What class are you in?

例句：

Hey, what class are you in?

I'm in Mr. Smith's English class.

Oh, I'm in that class too. Nice to meet you.