情态动词have to是属于例外的,疑问式须借助于助动词do的具体形式.例如：
I had to go home alone.
---Did you have to go home alone?
情态动词的疑问形式都是情态动词提前吗,有没有例外
情态动词have to是属于例外的,疑问式须借助于助动词do的具体形式.例如：
I had to go home alone.
---Did you have to go home alone?