I am doing sth. 翻译:我在做某事。
“What are you doing?”是用来询问你现在正在干什么(英语语法:现在进行时)。一般回答用I am doing sth。
比如:What are you doing?
I am watching TV./ I am reading a book./I am eating an egg/I am writing the homework/ I am playing the guitar/I am listening the music.
翻译:我在看电视/我在看书/我在吃鸡蛋/我在写作业/我在弹吉他/我在听音乐。
延伸
1、提问:What is he/she doing? 翻译:他/她在干什么?
回答:He/She is playing. 翻译:他/她在玩。
2、提问:What are they doing?
回答:They are chatting. 翻译:他们在聊天。