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.