忙什么呢在英语中可以说作 "What are you busy with?" 或者 "What's keeping you busy?"。这个短语源于汉语，主要用来问人正在忙于做什么。例如：

A: Hey, John, what are you busy with?

B: I'm working on a big project for my boss. It's due next week.

A: Hi, Mary. What's keeping you busy these days?

B: Oh, I'm taking care of my little sister while my parents are on vacation.

在这些例句中，"What are you busy with?" 和 "What's keeping you busy?" 都是询问对方正忙于做什么的问句。