Unit 5 Discovering useful Structures ppt课件 -（2021新）人教版高中英语必修第三册.pptx

1、Discovering useful structures in B3U5 Leading-inMay we ask what youre doing in this country and what your plans are?I cant say that I have any plans.You mustnt worry about that.Could you offer me work here?Read the sentences below and think about:What are the functions and meanings of these modal ve

2、rbs?A. necessity B. possibility C. obligation D. request E. advice F. intentionThe functions of modal verbsYou have to read between the lines because the real messages are often hiddenIt may seem lucky to you.Astronauts must wear spacesuits when they work in space because May we ask what youre doing

3、 in this country? You should/ought to/had better go to class right away.What would you do if you were in her situation?necessity 表必表必要性要性possibility 表表可可能和推测能和推测obligation 表义务性表义务性request 表请求或指示表请求或指示advice 表建议表建议intention 表意图和愿望表意图和愿望A. necessity B. possibility C. obligation D. request E. advice F.

4、 intention情态情态动词动词1. 情态动词有一定的意义情态动词有一定的意义，表示或暗示某种情绪或，表示或暗示某种情绪或态度，态度，表示可表示可能、建议、愿望、必要、允许、能力等。能、建议、愿望、必要、允许、能力等。 大多数情态动词有多大多数情态动词有多个意义。个意义。2. 情态动词没有人称和数的变化情态动词没有人称和数的变化，即不随主语的不同而变化。，即不随主语的不同而变化。 3. 情态动词不能独立使用，须后接动词原形，一起构成谓语动词。情态动词不能独立使用，须后接动词原形，一起构成谓语动词。4. 情态动词除情态动词除ought和和have外，外，后面接不带后面接不带to的不定式。的不

5、定式。(dare)5.情态动词没有非谓语形式，情态动词没有非谓语形式，即没有不定式、分词等形式。即没有不定式、分词等形式。Review of modal verbs1.只作情态动词的：2. 可情态可实义的： 3. 可情态可助动词的: 4. 相当于情态动词的: 情态动词的分类can/could, may/might, ought to, mustneed, dare/daredshall/should, will/wouldhave to, used tocan & could能力，猜测，请求能力，猜测，请求, 许可许可1.Some of us can use the computer now,

6、 but we couldnt ten years ago.2.You can have my seat. I am going now.3.Could I have a drink of water, please?4.Can he still be alive after all this time?5.If youre not careful, you could get into even worse trouble.能力能力许可许可请求请求猜测猜测猜测猜测ucould 表请求，比表请求，比can更委婉。更委婉。uCould表推测的可能性比表推测的可能性比can 小小can/ coul

7、d have donecant/ couldnt have done1. You _ (have) a better mark if you went over the vocabulary.2. I saw him just now, so he _ (go) abroad.could have had couldnt been gone 本可以本可以否定猜测否定猜测注意注意can 的惯用语的惯用语 On hearing the story , I cannot help laughing . You cannot be too careful with them. You cant be

8、careful enough.cannot help + 动名词动名词 忍不住做某事忍不住做某事cannot too /enough “无论怎么样无论怎么样.也不为过也不为过,越越越好越好” may 和和 might May I have a look at your book? You may use may dictionary so long as you return it before 7:00. He may be waiting for you at the station. They may have got lost.可可能性能性许许可可请求请求may/might have

9、done过去的猜测过去的猜测当句中出现当句中出现 “I am not sure” 等表示等表示不确定含义不确定含义的时候的时候,常选常选用用may 和和might .I _( may/can) go, but I am not quite sure.可能可能性：性：can could may might1. 对对may的一般疑问句的的一般疑问句的肯定回答肯定回答可用可用may或或can, 但作但作否定回否定回答答时要用时要用mustnt或或cant。May (Might) I have a little brandy?No, you mustnt. Youd better not.2. May

10、可以表示祝愿或希望，而可以表示祝愿或希望，而might不行。不行。May they be very happy in the future.May you succeed in the coming year.will 和和 would1. Ask, if you will, who the owner is.2. My friend asked if I would go with him.3. Will/Would you please have a coffee for me?4. This kind of clothes wont wash easily.5. Thats just l

11、ike hershe would lose her bag in the bus!意愿意愿过去的意愿过去的意愿请求请求习惯习惯would比比will客气委婉客气委婉I will tell you something important tomorrow.Will you marry me?（助动词）（助动词） （情态动词）（情态动词）1. 在在一、三人称一、三人称的疑问句中的疑问句中, shall用来询问对方的意愿。用来询问对方的意愿。Shall we begin our lesson? 2. 用于用于二、三人称二、三人称的陈述句中的陈述句中, 表说话人命令、警告、允诺等口吻。表说话人命令、警

12、告、允诺等口吻。He shall have the book when I finish reading.shall 和和 shouldYou should be polite to your teachers.3. should表示劝告、建议、命令，用于各种人称。表示劝告、建议、命令，用于各种人称。4. should表示说话人的惊讶、愤怒、失望等特殊情感，意为表示说话人的惊讶、愤怒、失望等特殊情感，意为“居然，竟然居然，竟然”。Amazing! You should wear slippers at work.1.You should have asked for some help.2.

13、You shouldnt have told her the news. should have done 表示表示本该做某事（而实际上未做）本该做某事（而实际上未做） shouldnt have done 表示表示本不该做某事（而实际上做了）本不该做某事（而实际上做了）1)must: 肯定句表有肯定句表有把握的推测把握的推测:“一定一定”。2)must: 推测现在或正发生的事情推测现在或正发生的事情：must be doing， eg: 他现在肯定呆在那里。他现在肯定呆在那里。He must be staying there.3) must 推测已经发生的事推测已经发生的事：must hav

14、e doneI didnt hear the phone. I _(我刚才没有听到电话，我想必是睡着了。我刚才没有听到电话，我想必是睡着了。)must have been asleep canteg: She cant have left school, for her bike is still here.mustmust用于一般疑问句中用于一般疑问句中,肯定肯定: must 否定否定: neednt/dont have to（不必）（不必），mustnt表示表示“禁止，不允许禁止，不允许” Must I finish all assignments at a time? Yes, you_

15、. No, you _ . mustneednt / dont have toPracticeComplete the following sentences using modal verbs.1. 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

16、. I havent decided where Im going for my holidays. I _ go to Australia.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. Th

17、ey _ arrive at any time.mustcantshouldmayshallwillmightwill / could过去将来时过去将来时( The Past Future Tense) 过去将来时表示在过去某一时间将要发生的动作或存在的状态。过去将来时表示在过去某一时间将要发生的动作或存在的状态。过去将来时常用在主句谓语动词为过去时态的宾语从句中。过去将来时常用在主句谓语动词为过去时态的宾语从句中。过去过去将来时句子中有时包含时间状语将来时句子中有时包含时间状语 the next day、soon等。等。过去将来时，表示从过去某一时间来看，将要发生的动作或存在的状态。1. I

18、 asked him if Peter would arrive the next day.2. She told me she was going to post the parcel. 3. We were about to go there when it begin to rain.4. She didnt say when she was coming again next time.5. I felt nervous because I was soon to leave home for the first time.6. We were to have been married

19、 last year.1. would/should+动词原形动词原形2. was/were going to+动词原形动词原形*与与would+动词原形动词原形相比，相比，was/were going to+动词原形有动词原形有打算、计划打算、计划的含义。的含义。3. was/were about to do4. go, come, leave, start, meet等动词的等动词的过去进行时过去进行时，表示就过去的某，表示就过去的某一时刻而言一时刻而言即将发生即将发生的动作。的动作。5. was/were to do; 表示曾经计划做某事，并且从现在看已经实现。表示曾经计划做某事，并且从

20、现在看已经实现。当表示当表示“原计划做某事但是最终未发生原计划做某事但是最终未发生”，用，用was/were to have done.Complete the following sentences that describe the future using either form of the given verbs. 1. Philip bought two tickets for The Phantom of the Opera. He _ _ (watch) with his girlfriend on the weekend.2. I was so surprised at th

21、e news that David _ (play) the role of the dinosaur in the play that I gave him a hug out of joy.3. Lily decided that she _ (settle) in New York and pursue her dream of becoming an actress.4. Hey, Timmy. I _ (call) you. But now that you are here, I dont have to.5. The competition was so close that no one was sure who _ (win)the Best Actor award6. Jim is not here right now. He said he _ (be) on duty at the library this afternoon. would watch / was going to watchwould play / was going to watchwould settle / was going to settlePracticewas going to callwould winwould be / was going to be