he has a headache Q:does he have a headache Q:What does he have?N:he doesn't have a headache.

问题描述:

he has a headache Q:does he have a headache Q:What does he have?N:he doesn't have a headache.
是不是疑问句和否定就要用have,肯定句就用has?

不是.因为这个地方have 是实义动词,does 提前第三人称单数才用have为什么第一句不是have第二句才是不是否定,也不是疑问,不需要助动词does,单数第三人称就用has我问的是为什么does he have a headache?这句为什么要用have一般疑问句,助动词does提前,所以用原形为什么最后句也是用have呢不是第三人称单数吗?在否定句中,doesn't提前了,所以也用原形