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(共21张PPT)
Grammar
Book 3 Unit 5
Express modality and talk about future events in the past
01
情态动词的定义与作用
情态动词的定义与作用
情态动词是一种本身有一定的词义，表示说话人的情绪、态度或与语气的动词，但不能单独作谓语，只能和其他动词原形构成谓语。
情态动词可以用来表示 necessity（必要），possibility（可能），obligation（义务），request（要求），advice（建议），intention（意图），permission（许可），prohibition（禁止） 等等。
Permission
Permission
说出下列句子中情态动词有什么作用
A. necessity B. possibility C. obligation D. request
E. advice F. intention G. permission H. ability
1. Oliver believes that with a million-pound bank note a
man could live a month in London.
2. Would you step inside a moment, please
3. Good morning, sir, would you please come in
4. May we ask what you're doing in this country...
5. Well, I can't say that I have any plans.
H
D
D
D
B
6. Well, you mustn't worry about that.
7. Could you offer me work here
8. If you don't mind, may I ask you how much money...
9. Well, it may seem lucky to you but not to me.
10. If you'll excuse me, I ought to be on my way.
11. You mustn't think we don't care about you.
12. You can't open it until two o'clock.
A. necessity B. possibility C. obligation D. request
E. advice F. intention G. permission H. ability
A
D
D
B
F
G
G
02
常见情态动词的用法
1. can & could
1. 都可表示“能力” could是can的过去式，表示过去的能力。如：
She can/be able to sing the song in English.
I could read when I was four.
2. could也可不表示时态 , 表示委婉的请求，（在回答中不可用could）
—Could I have a look at your notebook
—______________________________.
3. 表示“推测”(主要用于否定句,疑问句和感叹句中)
—Can it be Li Ming —No, it can’t be him.
4. can’t/couldn’t have done指对过去的否定推测，表示：不可能做了某事。
He can’t/couldn’t have gone abroad. I saw him just now.
Yes, you can.
No, you’d better not.
2. may & might
1. may和might 一般问句中表委婉的请求,肯定回答用______,否定用
__________________。
----May I use your pencil
----___________________________
2. may和might表示“可能性”, might暗示的可能性更小.
She may not be working now.
John might be at home now.
3. 对过去发生的事情的可能性作出判断用___________________。
She ______________________________the cinema(go).
may
you’d better not
Yes, of course/you may.
No, you’d better not.
may / might have done
may/might have gone to
3. will & would
1. will和would表示_________，可用于各种人称.
If you will help me with my English, I will be very happy.
I promised that I would do my best.
2. 在疑问句中,用于第二人称, 表示请求或征求意见, ________语气更委婉.
Will you tell him the news as soon as he comes back？
Would you please speak again more slowly？
意愿
would
3. 表示习惯和倾向性
will表示现在的习惯，would表示过去的习惯。
Oil will float on water. 油总是浮在水上。
When he was a child, he would often go skiing.
他小时候经常去滑雪。
will & would
4. shall & should
1. shall用于第二、三人称陈述句表示允诺、警告、命令、决心等。
You shall do as I say. ( )
Tell him that he shall have the book tomorrow. ( )
Nothing shall stop me doing it. ( )
2. 在疑问句中, 用于第一、三人称，用来表示请求或征求意见。
Shall I open the window for you？（征求意见）
3. should表劝告、建议、责任，义务
Young people should learn how to use computers.
You should take care of you family.
4. should have done表示责备或惋惜语气, 意为________________,
其否定shouldn’t have done表示____________________。
命令
允诺
决心
本应该做某事却没有做
本不应该做却做了
5. must & can’t
1. must用于一般问句中表是义务, 肯定回答用Yes, you must,
否定回答用__________________________________。
— Must I finish all assignments at a time
— _____________________________________________。
2. mustn’t 表示_________。
You mustn’t get down while the car is still moving.
3) must 也可表示对现在的肯定推测，
对过去的肯定推测用：must have done
It must be Li Ming.
It must have rained last night, since the ground is wet.
No, you needn’t. 或者 No, you don’t have to.
Yes, you must./ No, you needn’t.
禁止
6. need
1. need表示需要、必须，主要用于否定句和疑问句中，其否定形式为needn't，意为“没有必要，不必”。用need提问时，肯定回答为must，否定回答为 needn't 或 don't have to。
2. dare 作为情态动词，多用于否定句、疑问句或条件句中，无第三人称单数形式，只有一般现在时和一般过去时。
Dare he tell them what he knows
He dared not argue with his parents.
—Need I stay here any longer
—Yes,you must. —No, you needn't. /don't have to.
7. ought to
ought to表示“应该；应当 ”，可以表示有责任或义务而做某事。没有人称、数和时态的变化，否定式为 ought not to。
They ought to apologize.
Such things ought not to be allowed.
He oughtn't to have been driving so fast.
ought to与should一般来说，两者可以互换，只是ought to的语气略强。另外，表示出于法令规则、行为准则、道德责任等客观情况而“应该”做某事，通常用ought to；若用should则含有个人意见，强调主观看法。
You are older brother. You ought to take care of your little sister.
You should not waste time in watching TV.
03
情态动词表示过去将来
过去将来时表示从过去的某一时间来看将要发生的动作或呈现的状态。过去将来时常用于宾语从句和间接引语中。
常用来表示过去将来的结构：
was/were going to do
was/were about to do
was / were doing
would do
1. would do
1. 表从过去某一时间来看将要发生的动作。(尤其用于宾语从句中)
He promised that he would help me.
他答应他会帮助我。
2. 表示过去的习惯：即过去的动作习惯或倾向。
When I worked on a farm, I would get up at 5 a.m.
我在农场劳动时，总是早上5点钟起床。
used to do也可以表示“过去常常做某事”，暗含现在已经不这样做了，而would do只表示过去做某，不涉及现在。
2. was/were going to do
1. 表示过去的打算。
2. 根据现有迹象，表明将有某事发生。
My friend said he was going to watch the movie with his mom.
我朋友说他要和他妈妈一起看电影。
It seemed it was going to rain.
看上去天要下雨了。
He looked as if he was going to get mad.
他看上去他要发火了。
3. was/were about to do
表示即将要发生的动作，强调动作马上就要发生。由于本身已含有“即将”的意味，所以不再与表示具体的过去时间状语连用。
I was about to go to bed when the phone rang.
他进来时我正要离开。
4. was / were doing
表示在过去看来，将要发生的动作。可用于该句型中动词为come, go, leave, arrive, begin, start, 等动词。
Jack said he was leaving tomorrow.
杰克说他打算明天动身。
She didn't say whether she was coming to lunch.
她没有说她是否来吃午饭。
Complete the sentences:
1. He promised he __________ call me from Egypt.
2. I ___________________ put the roast in the oven when the doorbell rang.
3. They _________________ take out the trash but they were tired.
would
was about to
were going to
4. The plane ________________________in ten minutes.(arrive)
was arriving

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