问做什么事情,就用 what about you
问怎么样或怎样做,就用how about you
carlos19900105 的例子能说明区别：
例（1）
A：i like english ,chinese and math,what about you?
B：me too.
此例中A 问对方喜欢“什么语言”,即:I am asking "what language",and the question is "about" you --- what language you like.所以：What about you?
例（2）：
A：i take school bus go to school,how about you?
B：bike.上
此例中A 问对方怎样去,即：I am asking "how to go to school",and the question is "about you" --- how you go to school.所以：How about you?