一、 have to 的陳述句形式：
A、 肯定式：have to + 動詞原形
1、 I have to tidy my room.我得整理房間.
2、 She has to help with the washing.她得幫忙洗衣服.
B、 否定式：don't (doesn't) + haveto + 動詞原形
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 的一般疑問句形式及簡略答語：
have to的一般疑問形式必須借助助動詞 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?吉姆必須做家庭作業么?
Yes,he does./ No,he doesn't.是,他必須做./不,他不必做.