DO 后面跟是动词啊, eg:do you know? 而are 后面跟的是形容词 eg:are you fine?
主系表结构用Are you ,例如Are you a student?主谓宾结构用Do you ,例如Do you do your homework?
这和你后面要接的是动词还是BE动词有关。比如:have是个动词,所以他要用Do you have an apple?而像BE 后面则要跟一些adj之类的,如:happy,Are happy?