(共18张PPT)
情态动词表义务和需要
语法精讲
典例精析
1. must可用来表义务，翻译为“必须”。
例：I don’t like this TV set. We must buy a new one.
He must work hard to achieve his goals.
情态动词表义务（1）
强调说话人的主观看法
典例精析
2. have to可用来表义务，翻译为“不得不”。
强调客观需要，并且能用于多种时态。
例：I’m very tired and I have to stop to rest for a while.
He had to stay in bed because of his illness.
情态动词表义务（2）
典例精析
3. shall用于条约，规定，规章等文件中。
表示一种义务，多用于第三人称中。
例：It’s required in our regulation that students shall go to school on time.
Students shall remain in the seats until all the papers have been collected.
情态动词表义务（3）
典例精析
4. should表示“应该、必须”，通常表示自己的主观看法。
例：The boys shouldn’t be playing football. They should be at school.
We should protect our environment.
情态动词表义务（4）
典例精析
ought to表示义务，重于反映客观情况或涉及义务和规定，语气较should强。
例：You ought to take care of the baby.
You ought to be earning your living at your age.
should与ought to
1. My mother brings me up and takes good care of me, so when she is old I ought (look) after her in return.
解析：ought to表示义务，重于反映客观情况或涉及义务和规定。
语法填空。
考点追击
to look
2. There was no more bus. They (have) to walk home.
解析：have to可用来表义务能用于多种时态。根据语境句子用一般过去时。
had
情态动词表可能和猜测
语法精讲
概述
情态动词中的must, can, could, may, might，will，would，should，ought to都表可能与猜测。
用法1
1. 肯定句中一般用must (一定)，may (可能)，might / could (也许，或许)表可能和猜测。
例： You’re Tom’s good friend, so you must know what he likes best.
Your mother may/might know the truth.
1. 肯定句中表可能和猜测
用法2
例：It can’t/couldn’t be the headmaster. He has gone to America.
He may not/might not know the scientist.
2. 否定句中表可能和猜测
2. 否定句中用can’t / couldn’t(不可能)，may not/might not(可能不)表可能和猜测。
用法3
3. 疑问句中用can/could (能…… )表示可能和猜测。
例：Could he have finished the task
Can he be at home at present
3. 疑问句中表可能和猜测
例：1.The clouds are gathering. I’m afraid it might be pouring down soon.
2. The plane could be delayed by fog today.
典例分析
强
must
can/could
may/might
弱
may和can的过去式？
Attention:
表示语气更加委婉或可能性较小
4. should/ought to表可能和猜测时，意为“想必会，理应……” 。
用法4
例：It’s seven o’clock. Jack ought to/should be here at any moment.
There shouldn’t be any difficulty about getting you a visa.
4. should/ought to表可能和猜测
1. Peter may come with us last night, but he wasn’t very sure then.
解析：may和might都可以表示可能和猜测，句子为过去时，要用过去式might。
改错。
考点追击
might
2. It mustn’t be his father. He has gone abroad.
解析：mustn’t表示“禁止”，can’t表示“不可能”。
can’t
Bye-bye!(共16张PPT)
情态动词表愿望
语法精讲
用法1
1. will可用来表愿望，用于各种人称。表现在的愿望、意愿。
例：I’d like to go to the park with you if you will offer me lunch.
If you will wait a moment I’ll see whether Mr. John is free.
情态动词表愿望（1）
用法2
2. would也可用来表愿望，用于各种人称。通常表示过去的愿望、意愿。
例： She asked me if I would go with them.
Would you recommend the book to him
情态动词表愿望（2）
表现在的愿望或意愿，语气更委婉
3. 表愿望还可以用would like to或would love to，表示“想要；愿意”。
用法3
例：I would like to have dinner with my family tonight.
I’d love to play football with my friends this afternoon.
情态动词表愿望（3）
4. 表愿望还可以用would rather，表示“情愿”。
用法4
例：I would rather wait till tomorrow.
I would rather solve my problems alone, whatever they may be.
情态动词表愿望（4）
5. may也可以用来表愿望，但语气较正式。
用法5
例：May she enjoy her life!
May you both have a good journey!
情态动词表愿望（5）
1. I would like (choose) the red pencil.
解析：would like to表示“想要；愿意”，用来表愿望、意愿。
语法填空。
考点追击
to choose
2. He said he (will) try his best to help me.
解析：would用来表过去的愿望、意愿。用于各种人称。
would
情态动词表许可或禁止
语法精讲
典例分析
表示现在或将来的许可用may或can，译为“可以”。
表示过去的一般的允许用could或might。
例：I can/may take a day off whenever I want.
On Sundays we could/might stay up late.
情态动词表许可
典例分析
1. 可以用can’t、couldn’t或may not。
例：You can’t go out to play now.
I’m afraid you couldn’t sit here.
You may not come late next class.
情态动词表禁止（1）
语气较弱
更委婉
2.可以用shouldn’t“不应该”，含有责备的意思。
典例分析
例：You shouldn’t be so lazy.
You shouldn’t leave without say a word.
情态动词表禁止（2）
3.可以用mustn’t，翻译为“禁止；千万别；不能” 。
典例分析
例：You mustn’t go swimming today.
You mustn’t drive so fast.
情态动词表禁止（3）
语气较强
1. She said that he _______ (can) use her computer.
解析：表示过去的一般的允许用could。
语法填空。
考点追击
could
2. You play football in the street. You’ll get run over.
解析：mustn’t表示“禁止” 。
mustn’t
Bye-bye!
