DOES HE CAN SING?为什么不是Does can he sing?因为后面要跟陈述句 ，比如。do you have a cake ?不可以说成do have you a cakeMy father puts on his clothes and goes to work. 对my father提问， 是用who is put on……… 还是用who does用is。。。。does是对他提问，do does是助动词。is是系动词。不一样的