楼主的说法虽然符合语法,但容易产生歧义.用规范表达：What are you going to be when you grow up?
因为what will you do 英语中可以是“做具体某件事”,而不一定是指某人的职业.如What will you do tomorrow?(你明天将做什么?),而 What are you going to be when you grow up?是耳熟能详的专门问某人将来职业的问句.
楼主的说法虽然符合语法,但容易产生歧义.用规范表达：What are you going to be when you grow up?
因为what will you do 英语中可以是“做具体某件事”,而不一定是指某人的职业.如What will you do tomorrow?(你明天将做什么?),而 What are you going to be when you grow up?是耳熟能详的专门问某人将来职业的问句.