一般现在时态句子的谓语动词是实意动词的情况下，疑问句、否定句、一般疑问句的肯定及否定回答，都要用到助动词do或者does（主语是第三人称单数时用does，其它的用do)。例如

Do you go to school at seven?

Yes，l do. / No，l don't.

He doesn't(does not的缩写) have luhch at home.