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(共50张PPT)
Modal Verbs
情态动词
Fourteen Modal auxiliaries
Can --- could
May---might
Will---would
Shall --- should
Must
Need
Dare
Ought to
Used to
Main points
Ability and Possibility (表能力和可能)
Permission and Refusing (许可和不许)
Obligation and Necessity (义务与必然)
Prediction and predictability (预测与推测)
Willingness, intension and determination (意愿、意图与决心)
Warm-up tasks
1. Advocates of studying abroad believe students will reach new levels of intercultural understanding far exceeding what they ________ be able to accomplish just at home.
will B. would C. can D. could
2. Timothy Ray Brown, the first man cured of HIV，initially opted against the stem cell transplantation that _______ history.
could have later made
should have made later
C. might make later
D. would later make
Ability (能力) and Possibility (可能)
★
can, could, be able to
can, could, may, might,
1. Ability: can/could/be able to
can:
could:
be able to:
She could play the piano when she was six.
They were able to get everybody out of the burning building.
Can you call back tomorrow？
We can pass the exam after 4 months of study English grammar.
present or future
past
all-purpose (通用)
(general and specific)
(only general if positive)
(specific)
You’ll be able to get a taxi outside the station.
I haven’t been able to get much work done
today
She’d love to be able to play the piano.
Can, could or be able to
Edison always wondered why hens ______ hatch chickens while he ____________.
could
was not able to
A big fire broke out in ABC hotel yesterday. Luckily, everyone __________ run out of the building.
was able to
Be able to refers to managed to do it.
2. Possibility: could & may/might
1) could, may, might (用于肯定句):
time:
certainty:
Where are my keys
They could/may/might be in the car.
I could/may/might go to the party tonight.
Where was he last night
He _______________ have missed his train.
could, may & might: present and future
could＞may＞might
could/may/might
could/may/might have done: past
2) Can (in negative & question)
It can’t be true.
Can the news be true
The moon cannot always be at the full.
where can she have put it
In negative:
In question:
To be sure sth is not true. 肯定不真实
To express doubt or surprise.
究竟，到底，难道
He can be very tactless.
It can be quite cold here in winter.
We can eat in a restaurant, if you like.
I can take the car.
Sb /sth is often like
(常有的行为和情形)有时会，时而可能
To give suggestion (提建议)可以
Other meanings of can
She may not be at work.
They might not have left yet.
It is possible that she is not at work.
It is possible they have not left yet.
Negative transfer
Difference of may not and might not
1. A: Where is Tim
B: He might be next door.
What is the function of the modal auxiliary verb “might" in the reply
A. To express relief.
B. To dramatize a fact.
C. To indicate possibility.
D. To ask for permission.
Practice
Permission (允许) and refusing (拒绝允许)
can, may, could, might
may not, can not
1. Permission: can/may
Can/may I know your name
Yes, you can/may.
No, you can’t /may not.
Visitors may use the swimming pool between 7 a.m. and 7 p.m.
请求/给予许可
Refusing permission
ask for/give permission;
informal
polite & formal, often used in official signs and rules常用于正式标识和规定
▲Can & may:
Can:
may:
Could & might:
Do you think I could leave early
Yes, _______. /No________.
Might I have a word with you
Yes, _______. /No____________.
▲Could & might:
could:
might (BrE):
you can
you can’t
you may
you may not
/ mei n t/
ask for (not give) permission
more common
in polite way
2. Denying or refusing permission:
may not ,can not
May I smoke here
No, you ________.
Can I use your car for a few days
No, you ________.
may not
can not
(informal)
(You are not allowed.)
Obligation or duty (义务) and Necessity (必然)
must, have to, should/ought to
must, have to, need to
1. Obligation: must, have to
I must go to the bank and get some money.
Passengers must wear seat belts.
I have to share office with other teachers.
You should/ought to tell the police.
Must:
have to:
should/ought to:
duty through advice;
from the speaker;
from somebody else
1) Present obligation
—Must I go now
—Yes, you .
A. can B. must
C. need D. can go
—No, you .
A. mustn’t B. needn’t.
C. can’t D. don’t have to.
Answer to must
√
√
√
我们明天必须再试一次。
We will have to try it again.
你们昨晚必须借助烛光工作。
You had to work by candlelight.
2) Future obligation:
3) past ~ /
Will/shall have to
had to
past form of must:
2. Necessity: must, should, ought to
I must go to the bank and get some money.
▲must: the strongest
Are we supposed to show our ID cards
Is it necessary to apply for a visa
ls there a legal obligation to wear a bike helmet here
Other ways to ask about obligation
be supposed to:
to be expected or required to do sth according to a rule, a custom, an arrangement. etc. （按规定、习惯、安排等)应当，应该
Other meanings of must
to recommend that sb does sth (提建议) 应该，得
to emphasize a point that you are making必须 (用于表示强调)， 常与 I must say, I must admit连用。
We must get together soon for lunch.
This came as a surprise, I must say.
I must admit I like looking feminine.
Other meanings of must
If you must (do sth): sb may do sth but you do not really want them to
Must-see:必看；must-read必读；must-have必备
It’s from my boyfriend, if you must know.
Beijing is one of the world’s must-see cities.
(表示虽不赞同但可允许）如果你一定要
Other meanings of should
to show what is right, appropriate, esp. when criticizing sb’s action (纠正别人) 应该
to give or ask for advice (提出或征询建议）该
With I and we to give opinion that you are not certain about 与I和we连用，表示不确定。
to expect sth is true or will happen (表示预期)应该会。
You shouldn’t drink and drive.
Should I call him and apologize
I should say he is the just right man for the job.
We should arrive before dark.
2. We did hold a meeting yesterday, but you _______ , so we did not inform you.
A. did not need attending
B. needn’t attending
C. did not need to attend
D. needn’t attend
Jack—I have good news for you!
Rose—What
Jack—The educational department has carried out rules to reduce students' too much study burden.
Rose—Really If so, I don’t stay up late to do so much homework and my mom allow me to play computer games.
Jack—The best thing I think is that I have more spare time to take exercise after class.
Rose—Sure. By the way, who is your favorite movie star
Jack— Zhao liying, I say.
Rose—Tell me something about her.
Jack—Well, maybe I show you some photos.
have to
may
can
should
can
Blank-filling
Prediction and predictability
will/ shall
should, ought to
must, will, would
1. Prediction (预见)
I shall be away next week.
What time will he arrive
We will see you soon.
① both shall & will used to express prediction;
shall used with first person in BrE;
Will usu. used with all persons in AmE.
(future)
2. Predictability (猜测)
Should, ought to, must, will and would
Predictability expressed by will and would can be classified into：
1）Specific (特定事态) predictability,
2）Habitual (习惯性事态) predictability
3）Timeless (不受时限的客观过程) predictability.
2. Predictability (猜测)
You must be hungry after all that walking.
He must have known what she wanted.
I’m sorry, she’s not here. She must have left already.
现在非常肯定
过去非常肯定
Will & would: 特定事态推测
A: Who’s that man over there
B: That will be George, no doubt.
B: That would be George, I expect.
▲Both will and would refer to the present; would is less certain.
will和would都指现在的推测，would不太确定。
inference (推测) on present event
1) Specific predictability:
Will & would：习惯性事态推测
speculate about habits
will: the simple present (对现在的习惯进行推测)
would: the simple past (对过去的习惯进行推测)
Pauline will work all day without a rest.
Before his retirement he would catch the early bus every morning.
2) Habitual predictability
Will: 不受时限的客观过程
Timeless predictability refers to inference on the appearance of a phenomenon in an objective process. This use of will (but not would) is the same as the “timeless present”.
Oil will float on water.
= Oil floats on water.
If it’s made of wood it will float.
Always happens in a particular situation or generally true. 总是，某事经常发生或总是如此。
The degree of certainty:
might
may
could
can
should
ought to
would
will
must
uncertain
certain
That might be George.
That must be George.
Probability (大概率)
3. Among the four sentences below，Sentence _________ express the highest degree of possibility.
A. It may stake a long time to find a solution to the problem.
B. It might take a long time to find a solution to the problem
C. It could take a long time to find a solution to the problem
D. It should take a long time to find a solution to the problem.
Willingness, Intentions and determination
will, shall, would
shall, would
will, shall, would
Will & shall used in present and future; would in the past;
Will for willingness & shall for determination
1. Willingness: will, would
My sister will help you with the luggage.
I will check this letter for you, if you want
Will Alice accept the invitation
Would you pass me the salt, please
I asked him if he would help me with my writing.
▲will:
▲would:
With the 2nd and 3rd person in questions, someone is asked to do sth.劳烦别人做事。
past willingness & polite request
2. Intentions: will, shall
I will go to the party tonight.
You shall get a promotion.
= I’ll give you a promotion.
He shan’t come here.
= I won’t let him come here.
With 2nd & 3rd person subjects, shall may denote intention on the part of the speaker. (说话者的意愿)
3. Determination: will/shall
We shall fight on the beaches, we shall fight on the landing grounds...; we shall fight in the hills; we shall never surrender.
No one shall stop me.
= I don’t allow anyone to stop me.
(old-fashioned or formal)
I will win this singing contest.
I am the pilot, l will not take the responsibility. The plane is overloaded.
Shall
All payments shall be made in cash.
You shall not go.
Shall I send you the book
What shall we do this weekend
With I & we in questions for making suggestions or asking a question;
(fml) in official documents to state an order, law, promise….
dare
I dared to answer her.
He didn't dare go.
Dare he do it
I daren't try.
Usu. restricted to questions & negative sentences
(AmE)
e.g. I used to write poetry when I was his age.
I'm not used to getting up early.
A computer can be used to do accounts.
Used to
a) used to do:
b) be/get/become used to doing
= be accustomed to doing
c) be used to do
past states
past habitual actions
表示习惯于…
表示被用来做……
过去常常…
Negative form of used to
Tag question:
usedn’t to do (BrE)
didn’t use(d) to do (AmE)
didn’t / usedn’t
modals+ have +v+-ed： 表示过去
can/could/ may/might have done
过去可能…，本来可能…
2. must have done一定、肯定已经
3. would have done 本来会…
4. should have done 本来应该…，却没有…，表示遗憾
5. shouldn’t have done 本来不该…
6. needn’t have done 本来不需要…
4.“It‘s a shame that the city official should have gone back on his word.” The modal auxiliary SHOULD express _______.
A obligation B. disappointment
C future in the past D. tentativeness
5. Nancy's gone to work but her car's still there. She ____ by bus.
A. must have gone B. should have gone
C. ought to have gone D. could have gone
6. I ______ the plumber as I learnt later that John had already phoned him.
A. needn’t phone
B. needn’t have phoned
C. shouldn’t phone
D. shouldn’t have phoned
7. Which of the following sentences express a permission
A. You can’t park here.
B. I can’t finish the task in a weak.
C. He couldn’t have been hurt.
D. Where can he have gone
8. Miss Anne had a weak heart. She ______ a heart attack.
A. should have B. should have had
C. must have D. mut have had
7. Which of the following sentences express ability
A. You can’t park here.
B. I can’t finish the task in a weak.
C. He couldn’t have been hurt.
D. Where can he have gone
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