人教版高中英语必修三课件： Unit1 Festivals around the world Grammar情态动词 课件（共24张PPT）

课件24张PPT。Unit 1Festivals around the worldDiscovering
useful structures
--- Modal Verbs (I)
情态动词的语法特征
情态动词有一定的意义，表示或暗示某种情绪或
态度，表示可能、建议、愿望、必要、允许、能力等。
2. 情态动词没有人称和数的变化，即不随主语的不同而变化。
3. 情态动词不能独立使用，必须和实义动词一起构成谓语。
4. 情态动词除ought和have外，后面只能接不带to的 不定式。
5. ?情态动词没有非谓语形式，即没有不定式、分词等形式。 must
表示必须， 多处于义务、责任或强制命令(must提问，否定回答用needn’t或don’t have to).
You must hand in your homework today.
(2) mustn’t 表示禁止。意思是“不许”、“不准”、“不可以”。
You mustn’t smoke here.
(3) 用于发生了某种于说话人的愿望相反、不受欢迎的事时，意思是“偏偏”、“偏要”。
Why must he do it that way?
Why must it rain on Sunday?
(4) 表示推测， 只能用于肯定句。
He must be reading novels now.
The road is wet. It must have rained last
night.can /could
(1)表示能力
Can you speak Japanese?
(2)表示推测时，只用在否定句或疑问句中。
He can’t be at home now.
(3) 表示允许(许可或请求许可）
You can go now, but he can’t.
(4) 表惊异、怀疑等
How can you be so rude?could可表示能力或可能性，多用于过去，也可指现在，通常表示虚拟或作为can的委婉形式。can?/?could?+?have?done在肯定句中表示“本来可以做而实际上没做某事” ；在疑问句或否定句中表示对过去行为的怀疑或不肯定,?表示推测。 You?could?have?done?better,?but?you?didn’t?try?your?best.?
你本来可以做得更好，但你没努力。
?He?can’t?have?been?to?that?town.
他不可能去过那个城。may/might
(1)表示可能性，might比may可能性更小。
It may be true.
He might not come today.
(2) 表示请求、许可，多用于肯定和疑问句中
May I ask you a question?
(3) 表示愿望
May you be happy all your life.
might 比 may 语气更委婉
may/might表示推测时，表示对现在或将来要发生的事情把握不大。might/may have done表示对过去发生的动作进行的可能性推测。
He may have gone to the clinic.
他可能去医务室了。
He might have read about the news in the newspaper.
他可能已经从报纸上知道这个消息了。will/would
表示意愿，will表示现在的意愿，would表示过去的意愿。
Go where you will.
She asked if I would go with them.
2. 表示征求意见或提出请求，主要用于第二人称的疑问句中，will和would均可用，would此时并不表过去，而表示委婉语气。
Would Sunday night suit you?
Will / Would you please post the letter for me? 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(=used to do)。
Oil will float on water.
When he was a child, he would often go skiing.
4. 表示推测will用于谈论现在，would可用于谈论过去，也可用于谈论现在(语气较委婉)。? ??Ask him. He will know. ? ??Every family would have some sort of trouble. I thought you would have finished it by now. shall / should
1.在陈述句中,shall用于二、三人称表示允诺、警告、命令、决心等。
You shall do as I say. (命令)
Nothing shall stop me doing it. (决心)
Tell him that he shall have the book tomorrow. (允诺)2. shall在疑问句中, 用于一、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）
Shall he fetch some water for you？（请求）3. should常表示应当，意思和ought to相近，但语气较弱。
Young people should learn how to use computers.5. should have done表示责备或批评,意为“本应该…但”
You should have told her the truth earlier.
She shouldn’t have left without saying a word.4. should用于可能性推测时, 表“应该，很可能”
They left at 5:30. They should get there now.1. Jack described his father, who ____ a brave boy many years ago, as a strong–willed man. （2010 安徽卷）
A. would be B. would have been
C. must be D. must have been
答案：D
解析：句意为“杰克把他的父亲描述为一个意志坚强的人，他的父亲多年前肯定很勇敢”用must have been表示对过去事情的肯定推测。高考真题2. You _____ buy a gift, but you can if you want to. （2010 湖南卷）
A. must B. mustn't
C. have to D. don't have to
答案：D
解析：don’t have to 意为“没有必要”，符合语境，句意为：“你没有必要买礼物，但如果你想买的话，你也可以买。”3. I have told you the truth. ______ I keep
repeating it? （2010 江西卷）
A. Must B. Can
C. May D. Will
答案：A
解析： must 必须, 一定 can 可以, 能够， may 也许，will 意愿, 倾向性动作。前半句说我告诉你事实了, 这里用的是现在完成时, 表示过去的动作对现在造成了影响, 既然我已经说了, 我还必须重复一遍吗？4. I_______ have watched that movie —
it’ll give me horrible dreams. （2010山
东卷）
A. shouldn’t B. needn’t
C. couldn’t D. mustn’t
答案：A
解析：句意应为“我本来不应该看那部电影的----它会使我做噩梦的。”表示“本来不应该做而做了某事”用shouldn’t have done, 所以A项正确。 As he had heart attack, he was told that he
____ continue the work.A. needn't B. may not C. mustn't D. can't
2. An Englishman who ____ not speak Italian was once traveling in Italy.
A. must B. could C. may D. might
3. I ____ like to make a suggestion.
A. could B. would C. must D. might
4. I know things are hard with you, but you ____ try to get over the difficulties.A. can B. may C. must D. oughtC C B B Choose the best answers.5. We hope that as many people as possible
_____ join us for the picnic tomorrow.???? A. may B. must??? C. should D. can6. — I think I’ll give Bob a ring.????—You _____. You haven’t been in touch
with him for ages.???? A. will B. may ??? C. would D. should 7. — Could I have a word with you, Mum????? — Oh dear, if you ______.????A. can B. must??? C. may D. shouldDDB 8. It is usually warm in my hometown in March,
but it _____ be rather cold sometimes.
A. must B. can C. should D. would
9. You don’t have to know the name of the
author to find a book. You _____ find the
book by the title.
A. must B. need C. can D. would
10. Although this ____ sound like a simple task, great care is needed.
A. must B. may C. shall D. shouldB C B 11. You ______ be hungry already — you had
lunch only two hours ago!
A. wouldn’t B. can’t
C. mustn’t D. needn’t
12. According to the air traffic rules, you ___
switch off your mobile phone before
boarding.
A. may B. can C. would D. should
13. She ______ have left school, for her bike is
still here.
A. can’t B. wouldn’t
C. shouldn’t D. mustn’tB D A Complete the following sentences using modal verbs.You’ve been working all day. You ______ be very tired.
2. I wonder who that is. It _____ be Lisa. She’s in the library at this time.
3. It is a long time since we met last time. You _____ come and see us more often.
4. I haven’t decided where I’m going for my holidays. I _____ go to Australia.mustcan’tshouldmay5. My father’s birthday is coming. What
_____ I get him?
6. Why don’t you try on this dress? It _______
look nice on you.
7. --- Who was the man talking with your
teacher?
--- I’m not sure. It ______ be her brother.
8. I don’t know when the guests be here. They
_________ arrive at any time.willshallmightwill / could1. Finish the exercises in
Discovering Useful Structure.
2. Finish exercises in Using
Structures in Workbook.Homework