情态动词用法归纳
情态动词用法归纳
一．shall和will的用法
1、shall 用在第一、三人称，will 用于第二人称表示“征求意见”。
Shall I go now?
Shall we invite her, too?
Will you help me with the work?
Shall the reporters wait outside or what?
2、shall表示依据规定有义务去做。
Passengers shall not talk with the driver while the bus is moving.
3、shall 用于所有人称，表示说话人的许诺、威胁、警告、命令等。
You shall have an answer by tomorrow.
If he’s good, he shall have a new watch for Christmas.
If you children don’t do as I tell you, you shan’t go to the party.
4、would 可以表示过去的习惯（would 可表示反复发生的动作或某种倾向。used to 表示过去的习惯动作或状态，强调现在已不存在）
He would come to see me on Sunday when he was here.
The dog would lie there in the sun all afternoon.
When we were children, we would go skating every winter.
5、will可以表示“愿意”，而非将来:
I will pay you for it.
Go where you will.
We’re going on a climbing trip. Come if you will.
6、will可以表示倾向、习惯（总是会，老是等意思）
Sometimes the cat will lie there all morning.
Oil and water will not mix.
This machine won’t work.
二、can/could 的用法
1、表示具备某种能力。
The nine-year old boy can swim across the river.
Can you swim across the river?
We couldn’t get the truck to start.
2、表示“征询对方意见”和“允许”（could 语气委婉）。回答不用could.
Can /could I smoke here? Yes, you can. No, you cannot.
Could you tell me where John is?
3、表示“可能性”。（否定句疑问句常见,肯定句也可以）
Can/Could it be true? 那会/可能是真的。
That can’t/couldn’t be true. 那不可能是真的。
Will you answer the phone? It could be your mother.
三．may/might 的用法
1、表示“征询对方意见”和“允许”。
May I turn on the TV?
Yes, of course. Yes, you can/may.
No, you can’t/may not /mustn’t/I’m afraid not.
You may go home now.
2、表示可能性，“也许”。常用于肯定句。
You may/might have some fever.你也许发烧了。
He said that the news might be true.他说这消息可能是真的。
They may/might be having a bath.他们也许正在洗澡。
四．must的用法
1、表示“必须
Patients must use medicine according to the doctor’s orders.
2、表示推测，只用于肯定句。在否定句或疑问句中，用can/could：
There must be a mistake.
Can/Could there be a mistake
There can’t/couldn’t be a mistake.
3、注意must 的回答：
Must the ladies wear dresses?
yes, they must. No, they don’t have to. / they needn’t.
Can/May I come in? No, you can’t/ mustn’t.
4．表示禁止。
Children mustn’t go across the street alone.
五．表示“推测”的表达法总结
（1）表示对现在和将来状况的推测：must一定，may 可能，might 也许，can’t不可能。
（2）对已经过去的情况的推测，用“情态动词＋have+ done”结构：
①must have done 过去一定已经…（只用于肯定句中）
②can’t/ couldn’t have done 过去不可能--- （表示否定）
③may/might have done 可能已经----
④need n’t have done 本来不必做---
⑤could have done 那时本来可以…（在肯定句中，不可用can)
⑥should have done 本来应该做---（实际未做）
⑦shouldn’t/ oughtn’t to have done 本不应该做-----（实际做了）
He must have been drinking beer.他肯定一直喝啤酒来着。
The money can’t have been lost there.钱不可能是在那儿丢的。
He may have gone to bed.他可能已经上床睡觉了。
She might not have settled the problem.她可能尚未解决那个问题。
We could have solved the problem in a more reasonable fashion.
You should have come here ten minutes earlier.
She should / ought to have gone there alone.
六、need的用法
1、作为情态动词，need一般只用于否定句和疑问句中。
You needn’t try to explain. Need we stay here this evening?
2、Need 作为实意动词可用在所有句型中。
She needs to come tomorrow.
You don’t need any help from others. Do they need this?
七、dare的用法
1．做情态动词，通常用于疑问句，否定句和条件状语从句中。
