2019-2020学年中考英语语法备考10 情态动词(讲解)

（2）．表示肯定的推测：一定

He must be at home.（对现在的猜测）

I think you must have made a mistake.（对过去的猜测） He must be our new teacher. He can’t be our new teacher.

（3）此外还要弄清楚must与have to的区别 4．will与would 1）． will

（1）表示意愿、决心。此时可用于各种人称。

He won’t come to see you.他不愿来见你。（表示意愿）

I will try my best to catch up with her.我将尽最大努力赶上她。（表示决心）

（2）表示请求，此时仅限于“will you (please)…？”句型中，仅用于第二人称和疑问句中。 Will you please buy me an English-Chinese dictionary when you go to the bookstore? Will you have some rice? 2）． would

（1）will的过去式，表示过去的意愿和决心。

He said he would do everything for her, but she said she would never see him again. They believed that we would help them.

（2）用于现在时，表示委婉地提出请求，建议或看法。此时would的用法比will更加委婉。 Would you please show me the way to the museum? I would like to say something about it.

will和would用于“劝某人接受……”时，只能用some，不能用any。如： Would you like some fish? 吃点鱼好吗？ 5．shall与should 1） shall

征求对方意见或请求，用于第一、三人称。表示“要不要……？”、“……好吗？” Shall I open the window? Shall the doctor come? 2） should

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（1）should意思是“应该”，表示劝告或建议（=ought to） You should wash your hands before dinner. We should help each other. （2）用来表示可能性或猜测。 He should be in the office now. I should be right.

（3）should有时能表示说话人的情感等。

It’s funny that they should be confident.（表示轻视） Why should I do that for you?（表示不满）

（4）should后接动词不定式（不加to）时，若用于肯定句，表示某件事本应该完成却未完成；若用于否定句，则表示某事不该发生却发生了。

You should have told us the truth.（应该告诉却没有）

He should have known the importance of it.应该知道却不知道） We shouldn’t have left so early.（不应该早出来，可已经做了） 6．need

1）need意思是“需要，必须”，主要用于否定句和关系问句中。 You needn’t come so early. Need I take part in the Party?

2) need引导的疑问句，肯定回答时多用must，否定回答时用needn’t。 Need he come? Yes, he must. No, he needn’t.

3) need后接名词做宾语时，表示“需要”某件事物，此时用作实义动词，与一般的实义动词用法完全一样。如：

We need three apples.

He doesn’t need so many books. 7. ought

ought只有一种形式，后面常与to连用，意思是“应该”。 You ought to visit us often.

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Sorry, I ought to leave now.

在表示“应该”时，ought to的语气比should要强，比must稍弱。 8. dare

1) dare意思是“敢”，用于肯定结构中时，后接加to的动词不定式。 The boy dared to climb up the tree. She should dare to question her teacher.

2）dare用于否定句或疑问句中时，与大多数的情态动词一样，后接不带to的动词不定式。 Don't dare do that again! The poor girl dare not go home. 9．had better

You had better see a doctor. You had better not leave now. Had I better wait for her?

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