have to的用法总结归纳

　　一、have to 与其他情态动词一样也是后接动词原形，表示外界的强制作用，强调被迫性。含有不情愿的色彩，常译为“必须，不得不”。

　　二、have to 可用于多种时态，而且不同时态使用不同的形式：一般现在时中，主语为第三人称单数时用has to ; 一般过去时中，用 had to。 have to 还可以用在其他的情态动词之后。例如：

　　She has to look after her little sister.

　　她不得不照顾她的小妹妹。

　　I have to do some washing.

　　我必须洗洗衣服。

　　I had to do my homework last night.

　　昨晚我不得不做作业。

　　I think he may have to help his Dad in the garden.

　　我想他可能不得不在花园里帮他爸爸。

　　三、have to 的否定式和疑问式一般要借用助动词do的适当形式构成。have to 的否定式是don’t have to; has to 的否定式是doesn’t have to; had to 的否定式是didn’t have to。have to的疑问式同样也借用助动词do的相应形式构成。例如：

　　He doesn’t have to do the homework now.

　　他没有必要现在做作业。

　　—Do I have to go there now?

　　我现在就得去那儿吗?

　　—Yes, you do. (No, you don’t have to.)

　　是的，你必须去。(不，你不必。)

　　We didn’t have to answer the question yesterday.

　　昨天我们没有必要回答这个问题。

　　注：情态习语是助动词、不定式或副词的组合。

　　四、翻译下面的句子。

　　1.我们必须自己动手去做。

　　2.玛丽必须在英语学习上努力吗?

　　3.上周日他不得不早起。

　　4.你没必要为你的功课担心。

　　5.彼得很累，不得不坐下来休息一会儿。

　　6.昨天他不得不待在家里。

　　7.他不得不跑回学校取他的作业本。

　　8.你必须早些离开吗?

　　9.我没必要躺在床上。

　　10.我们必须认真听老师讲课。

　　keys:

　　1. We have to do it ourselves.

　　2. Does Mary have to study hard at English?

　　3. He had to get up early last Sunday.

　　4. You don’t have to worry about your lessons.

　　5.Peter was very tired and he had to sit down and have a rest.

　　6. He had to stay at home yesterday.

　　7.Hehad to run back to school to get his exercise-books.

　　8. Did you have to leave early?

　　9. I don’t have to stay in bed.

　　10.We have to listen to the teachers carefully.