What's Tom(doing) 为啥用doing不用doesing

What's Tom(doing) 为啥用doing不用doesing what s Tom doing?回答 what's tom doing什么意思如何回答? tom,what's your mother doing?------------oh she is busy_____ What's Jenny doing? What's the doing? What,s.she.doing? What's Tom's father doing?____ a,she' reading b,He's reading 改错:What's you doing? what's the boy doing? What's you doing now? What's your parents doing.