Unit 1 Festivals around the world 情态动词

(共26张PPT)
情态动词表说话人的某种感情
或态度，表示“需要、可以、
必须、应当”等。
情态动词 ( modal verbs)
情态动词的特征
1) 情态动词不能单独做谓语, 除ought和have外, 后面只能接不带to的不定式。
2) 情态动词没有人称, 数的变化, 但有些情态动词, 如can、will也有一般式和过去式的变化。
3) 情态动词的“时态”形式并不是时间区别的主要标志, 不少情况下, 情态动词的现在式形式和过去式形式都可用来表示现在时间、过去时间和将来时间。
1. can / could/ be able to
may/might
must/have to
shall/should/ought to
will/would/used to
dare/need
只作情态动词的 can / could, may /
might, ought to, must
可情态可实义的　 need, dare
可情态可助动词的 shall / should, will /
would
相当于情态动词的 have to, used to
1) Some of us can use the computer now,
but we couldn’t last year.
2) The new-built theatre can seat 1500 people.
3) Can she be in the computer center
4) I though what he said could not be true.
5) It can be very warm in winter here.
May I use your dictionary
1.表能力“能够”
3. 表示“请求” “允许”(表请求时，口语中常用may）
2. 表示推测，意为“可能”“或许”，用于疑问句或否定句
用于肯定句，表示理论上能 “有时会”
1. can
4. can 用于疑问句或否定句中时，表惊异、
不相信等，意思是“可能、能够”。
How can you say that you really understand the whole
Story if you have covered only part of the article
We all knew that the young man couldn’t be a doctor.
A. could 是can的过去式, 表示与过去 有关的能力和推测:
B. could可以代替can表示请求, 但语气更委婉:
could
---Could I use your computer
---Yes, you can
He could swim across the river
He was able to swim across the river
succeed in doing sth/manage to do
He ______ escape from the big fire yesterday
A could B must
Cwas able to D might
can 只能用于现在时，过去时
be able to 能用各种时态
be able to
2. may 与might
A. 表示许可或请求，“可以” ，口语中might 更委婉。
--- May/might I watch TV after supper
--- Yes, you may. / No, you mustn’t.
B. 表示推测。 “或许，可能”，一般有暗示词
“not sure“ might 比 may 可能性小。”
I am not sure，They may be in the library now.
may/ might as well + V原 “不妨…”
may well+V原 “很可能”
You may/might as well go and have a look.
You may/might well be right
D. May you +V原 表希望、祝愿 “祝你……”
May you succeed！
3. must/have to
A. must 表示主观上, “必须”
have to 表示客观上，“不得不”
1) I must work hard.
2) I have to work hard.
B. must表推测，用于肯定句，“一定”“准是”。
There is nobody here. They must have all gone
home.
C. must表示“非要，偏要”
If you _______ smoke, please go outside.
If you __ go, at least wait until the storm is over.
A. can B. should C. must D. may
E. mustn’t　“禁止”
Mustn’t play with fire！
D. must提问
---Must we finish the work tomorrow
---No, you needn’t/ don’t have to
4. will 与would
A. 表请求、建议等，用 would 比will 委婉
1)Will you lend me your book
2) Would you like a cup of tea
B. 用于表示意志或意愿。 will 指现在，
而 would 指 过去。
Eg: 1) I’ll do everything for you.
2) They said that they would help us.
C.表示某种倾向或习惯性动作。 译 “总是、惯于”
will 指现在，would 指过去。
1) He will often read all night.
2) Every evening, she would sit by window, deep in thought.
3) He used to read all night.
高考：This door won’t open.
这门总也打不开
5. shall 与should
A. shall用于第一、三人称疑问句，表征询意见，
1) Shall we begin our discussion
B. shall用于第二、三人称陈述句，表示说话人
的允诺、警告、命令，决心等语气。
1)You shall get the book tomorrow.
2) He shall be punished.
3) You shall do as I say.
4) He shall become a good child.
允诺
警告
命令
决心
C. 用于条约，规章，法令等文件中，语气
远远大于must
一What does the sign over there read
一“No person ________ smoke or carry a lighted
cigarette，cigar or pipe in this area．”（2007 四川卷）
A．will B．may
C．shall D. must
The interest _______be divided into five parts, according to
the agreement.
should
A. 表劝告、建议。 ”应该、应当”。
You should keep your promise.
B. 表推测。 意为 “按理说应该…”
What do you mean, there are only ten tickets
There should be twelve
C. 表义务，“应该”，ought to “道义上应该”，更正式
You should/ought to be polite to the old
D. 表示惊奇，“竟然”
It is strange that you should be late !
6. need 与dare
A. 都可用于情态动词，一般是疑问句，否定句
1) ---Need I leave now
--- Yes, you must/No，you needn’t
2) He dare not go out alone
B. 都可用实义动词，后接to do，口语中常省to
1)You don’t need to do it
2)He didn’t dare (to) look up.
6. need 与dare
She _____ into the thick forest alone on such a
dark night
A dares not go B dares not to go
C dare not to go D doesn’t dare to go
高考热点：
一：情态动词表推测用法
肯定
定
推
测


í

ì
must
准是，一定
should
按理说应该
may/might/could
可能
，
也许
否
定
推
测


í

ì
can
’
t
或
couldn
’
t
不可能
shouldn
’
t
大概不会
may/might
not
可能不
，
也许不
may：一般用于_____和_____句
must：只能用于_____句。
肯定 否定
肯定
can：一般用于_____和_____句，用于____句，表示__________。
注意：
表推测时can/could, may/might没有时间上的差别，过去式更委婉
否定 疑问
肯定
有时会、
表推测时：
练习
1. A:Look, someone is coming. Who ______ it be
B: I’m not sure, It ______ be the headmaster.
A:It ______ be him. He has gone out.
B: Then it ______ be Mr Smith. He looks like the headmaster very much.
2. He is a man of few words, but ______ be quite talkative at times.
can
may
can’t
must
can
二、情态动词+have done
A.表示对过去的推测
1. must have done
2. may/might have done
3. can’t/couldn’t have done
注：在疑问句中 can/could 表示对过去情况的疑问性
推测，“可能做了吗？”
1. Someone broke into our bedroom, Who____ have done it
2.The ground is rather wet, it _____ have rained last night.
3.Tom ______ have gone to shanghai, but I still not sure about it.
4.The ground is very dry, so it ____ have rained last night
can/could
must
may/might
can’t/couldn’t
B对过去事情的责备
1. should/ought to have done
2. shouldn’t/oughtn’t to have done
3. could have done
4. needn’t have done
5. would rather have done
1.I really regretted wasting the hours when I
_________ have studied hard, but it was too late.
2. . ---- I stayed at a hotel while in New York.
---- Oh, did you You ____ stayed with Barbara.
3. Your home is not far from your school, so you
_______ have left in such a hurry.
4.I _______ have come to help you with your
English, but I was too busy at that time.
should
could
needn’t
would
三：推测时反义疑问句
*He must be at home now，_______
*He must be playing football now,______
*He must have tried his best yesterday,_____
*He must have tried his best,______
对什么时间的推测，反义疑问句用什么助动词？
现在
现在正发生
过去
过去
isn’t he
isn’t he
didn’t he
hasn’t he