don't have to的意思

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don't have to的意思

don't have to的意思
don't have to的意思

don't have to的意思
不是一定要
have to
have to通常指由于客观原因则不得不做某事,意思为“不得不”.
e.g.It's dark now.I have to go home.
天黑了,我不得不回家.
It's raining,and I have to stay at home.
外面在下雨,我不得不呆在家里.
一、have to与一般情态动词的异同
相同点:
一般的情态动词不能单独作谓语,后面必须接动词原形一起构成谓语,have to 也是这样.
不同点:
1、一般的情态动词没有人称和数的变化,而且所用的时态也受到一定的限制,而have to 有人称和数的变化.可用于多种时态中:一般现在时中当主语是第三人称单数时要用has to,其余的人称用have to,一般过去时中要用had to; 一般将来时中则要用will have to.
e.g.She has to go to school by bus.
她不得不乘公汽上学.
You'll have to see the doctor if you get ill.
如果你生病了,就得去看医生.
2、否定句和疑问句的构成方式不同:
①一般的情态动词直接在后面加not构成否定句,把这些情态动词提到句首就构成一般疑问句.
②而have to 的否定句和疑问句的构成往往要借助于助动词do的适当形式或助动词will即have to,has to,had to和will have to的否定式分别为don't have to,doesn't have to,didn't have to和won't have to,疑问句是在句首加助动词do的相应形式,句中还原成have to或把will放到句首,这里have to简直就是一个十足的行为动词.
e.g.What does she have to do?
她必须做什么?
You didn't have to wait for me yesterday.
昨天你没有必要等我

没有必要 needn't

不需要

不必 不需要

没必要 不需要 不必