1、Unit 1,Festivals around the world,Modal Verbs,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neednt或dont have to). You must hand i
2、n your homework today. (2) mustnt 表示禁止。意思是“不许”、“不准”、“不可以”。You mustnt 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 Ca
3、n you speak Japanese? (2)表示推测时，只用在否定句或疑问句中。 He cant be at home now. /Can this be true? (3) 表示允许(许可或请求许可） You can go now, but he cant. (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 co
4、uld have done better, but you didnt try your best. 你本来可以做得更好，但你没努力。He cant have been to that town. 他不可能去过那个城。,注意: 1).could也表请求,语气婉转,主要用于疑问句,不可用于肯定句,答语用can Could I come to see you tomorrow?Yes,you can. ( No, Im afraid not.),2)can表能力时,可用be able to代替,但表某事经过努力已成功时,应用be able to. He was able to flee Europ
5、e before the war broke out. = He managed to flee Europe before the war broke out,2. may (might) a). 表示说话人同意,许可或请求对方许可,might 比may语气更加婉转,否定用mustnt.You may take the book home./ May I come in?- May I use your dictionary? -Yes, you may. ( No, you mustnt.)注意：用May I征求对方的许可比较正式，语气比较客气；而用Can I.常用于口语中.,b). 表猜
6、测,可能性(主要用于肯定句和否定句中).might 更不肯定He may be very busy now.Tom may not be eighteen.,c). 用于祈使句中表示祝愿May you succeed!,3. must 和 have toa). 必须,应该, 表示说话人认为有必要做某事(否定回答用 neednt, dont have to) -Must we hand in our English exercise books? -Yes, you must. ( No, you dont have to.),Peter _come with us tonight, but h
7、e isnt very sure yet. A. must B. may C. can D. will,may/might as well，后面接不带to 的不定式，意为“不妨” “倒不如”。 You may as well stay here over the night.,c). must 和 have to 的区别: 1. must 表示说话人的主观思想, have to 表示客观需要。You must do it now. (说话人认为必须现在干)I have to go now. (客观条件必须现在走)2. must只有一种形式,have to有更多的时态形式3.询问对方的意见时,
8、用mustMust I clean all the room?4.二者的否定意义不大相同 You mustnt goYou dont have to go.,b).对事物的推测,用于肯定句中,否定用cant- He must be in the classroom. -No, he cant be.,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。,4.
9、need 和 darea). need 需要 ,多用在否定式或疑问句中.Need I attend the meeting tomorrow? You need not hand in the paper this week.,need 是一个情态动词, 它的用法完全和其他情态动词一样, 但 need 还可当作实义动词使用, 这时 need 就象其他动词一样,有第三人称,单复数, 后面加带 to 的动词等特性。I need a bike to go to school. Do you need a dictionary? She needs a necklace.,b). dare 敢, 多用
10、在否定,疑问句和条件状语从句中。一般不用于肯定句中。The little girl dare not speak in public. Dare you catch the little cat?,I dare say 是一个固定搭配。表示“我猜测，可能、或许”后面一般跟从句。 I dare say he will come.,dare 除用作情态动词外,更多的是当实义动词使用, 用法同实义动词一样,要 考虑人称,单复数,时态等。 I dare to swim across this river. Do you dare (to) walk in the dark? He doesnt dar
11、e (to) tell the teacher what happened that day.,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 wil
12、l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.,7. used to( 否定式,疑问式,反意疑问句附加部分均
13、有两种情况) Did you use to go to the same school as your brother?Used you to go to the same school as your brother?,9. would rather do sth./ would rather not do sth.would rather sb did sth.,8. had better do sth./ had better not do sth,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 sa
14、y. (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
15、 have done表示责备或批评,意为 “本应该但”You should have told her the truth earlier.She shouldnt 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.,注意: 在反意问句中，表推测的情态动词,句中有过去时间状语的，问句部分用过去时，否则，用现在完成时。He must have been there yesterday, _? He must have been ther
16、e, _? He cant have been there yesterday, _? He cant have been there, _? He must be in the classroom, _?,wasnt he,hasnt he,was he,has he,isnt he,1. Jack described his father, who _ a brave boy many years ago, as a strongwilled man. （2010 安徽卷）A. would be B. would have been C. must be D. must have been
17、 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. mustnt C. have to D. dont have to 答案：D 解析：dont 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
18、? （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 itll give me horrible dreams. （2010山东卷）A. shouldnt B. neednt C. couldnt D. mustnt 答案：A 解析：句意应为“我本来不应该看那部电影的-它会使
19、我做噩梦的。”表示“本来不应该做而做了某事”用shouldnt have done, 所以A项正确。,As he had heart attack, he was told that he _ continue the work. A. neednt B. may not C. mustnt D. cant 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
20、. 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. ought,C,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. can 6. I think Ill give B
21、ob a ring. You _. You havent 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. should,D,D,B,8. It is usually warm in my hometown in March, but it _ be rather cold sometimes.A. must B. can C. should D.
22、would 9. You dont 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. should,B,C,B,11. You _ be hungry already you had lunch only two hours a
23、go!A. wouldnt B. cant C. mustnt D. neednt 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. cant B. wouldnt C. shouldnt D. mustnt,B,D,A,Complete the following sentences
24、 using modal verbs.,Youve been working all day. You _ be very tired. 2. I wonder who that is. It _ be Lisa. Shes 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 havent decided where Im going for my holidays. I _ go to Australia.,must,c
25、ant,should,may,5. My fathers birthday is coming. What _ I get him? 6. Why dont you try on this dress? It _ look nice on you. 7. - Who was the man talking with your teacher?- Im not sure. It _ be her brother. 8. I dont know when the guests be here. They _ arrive at any time.,will,shall,might,will / could,
