当句子有实意动词的时候，变
疑问句和否定句的时候，用
助动词do/ does/ did.
当句子没有实意动词而是有be (是
连系动词或助动词）的时候，就用直接用be的不同形式，提问。
如：Do you get up early? Does he like English?
Did he come to see you yesterday? (以上三句话都有实意动词）
再如： Are you a teacher? Is he watching TV?
Were you doing your homework at 7 last night? (这三句话都是be的不同形式）