一、 have to 的陈述句形式
A、 肯定式：have to + 动词原形
1、 I have to tidy my room.我得整理房间。
2、 She has to help with the washing.她得帮忙洗衣服。
B、 否定式：don't (doesn't) + haveto + 动词原形
1、You don't have to go if you don't want to.如果你不想去，你就不必去。
2、He doesn't have to stay at home all day. 他不必整天呆在家里。
二、have to 的一般疑问句形式及简略答语
have to的一般疑问形式必须借助助动词 do 或 does：
1、 Do you have to look after your sister？ 你得照看你妹妹么？
Yes, I do./ No, I don't. 是的，我得照看。/不，我不必照看。
2、 Does Jim have to do his homework? 吉姆必须做家庭作业么？
Yes, he does. / No, he doesn't. 是，他必须做。/不，他不必做。
三、have to 的特殊疑问句形式
1、 What do you have to do on Sundays?在星期天你得干什么？
2、 Why does she have to move to Paris?她为什么得迁往巴黎？
3、 Where do they have to work?他们必须在哪里工作？