新教材2020-2021学年英语人教版必修第三册课件：UNIT 5 DISCOVERING USEFUL STRUCTURES .ppt

1、Unit 5The Value of Money Discovering Useful Structures 情态动词(Modal verbs)和过去将来时(The past future tense)【情境探究】Dialogue 1:Dialogue 2:体会以上两个对话中的情态动词,并写出其含义。(1)can _(2)may _能,会可能【要义详析】情态动词(Modal verbs)一、情态动词表特别语气1.can/could(1)表示能力,意为“能,会”;could主要指过去的能力。*(2020全国卷)Then I can spare some time to learn it agai

2、n,so that we canpractice together every day.然后我就可以抽出时间重新学习它,这样我们就可以每天一起练习。*(2019全国卷)In these places patients can go to be near nature during their recovery.在这些地方,病人能够在康复过程中亲近大自然。*(2019天津高考)I had hoped to send Peter a gift to congratulate him on his marriage,but I couldnt manage it.我本来希望送给彼得一件礼物祝贺他结婚

3、,但没有做到。(2)表示请求或许可。当请求允许做某事时,两者均可用,但用could语气更委婉。当表示允许某人做某事时,一般要用can,而不用could。*Can/Could I use your bike tomorrow morning?Yes,you can.我明天早晨能用你的自行车吗?是的,可以。(3)表示惊异、怀疑、不相信等态度时,意为“怎么能,怎么会”,主要用于否定句、疑问句或感叹句中,用could时语气较委婉。*How can you be so careless!你怎么那么粗心呀!【知识延伸】can与be able to的区别can只能用在一般现在时,而be able to可用于

4、更多的时态。*He will be able to tell you the news soon.他将能够很快就告诉你这个消息。表示过去特定的能力或经过努力才具备的能力,只能用be able to。*I talked with her for a long time,and finally I was able to make her believe me.我和她谈了很长时间,最终,我让她相信了我。2.must表示现在或将来必须要做某事,多是出于义务、责任或强制命令,指说话人的主观意志。*(2019天津高考)Students must provide their presentations o

5、n CDs before Friday,March 23.学生们必须在3月23日周五之前提供他们的展示光盘。【名师点津】must用法点拨(1)回答must引出的问句时,如果是否定的回答,不能用mustnt,而要用neednt或dont have to。Must we hand in our English exercise books?我们必须交英语练习册吗?Yes,you must.(No,you dont have to./No,you neednt.)是的,你必须要交。(不,你不必)。(2)must用于疑问句中,可以用来表示责备、抱怨的感情色彩,意为“偏要,硬要”。mustnt的意思是“

6、禁止”,而不是“不必”。*Must you interrupt me now?Cant you see Im on the phone?你非要现在打断我吗?难道你没看见我在打电话吗?【知识延伸】have to表示“必须,不得不”,意义与must很接近,但must表示主观意志,而have to表示由于客观因素不得不做某事,并且可用于更多的时态。*(2019全国卷)I work not because I have to,but because I want to.我工作不是因为我不得不工作,而是因为我想工作。*We must promote our environmental awareness

7、 and behave ourselves.我们必须提高环保意识,并规范我们的行为。【即学活用】用适当的情态动词填空。(1)I should have been there,but I _ find the time.(2)Tom,you _ not leave all your clothes on the floor like this!(3)I sincerely hope you _ accept my invitation.(4)John,look at the time._ you play the piano at such a late hour?couldntmustcanM

8、ust3.may/might(1)表示请求时,两者都可用,只是 might 表示的语气较委婉(但并不表示过去);表示许可时,通常要用 may而不用might。*You may come in now.你现在可以进来了。(表示许可)*Might I have a look at your new computer?我可以看看你的新电脑吗?(表示请求)(2)may表示祝福与愿望,多用于书面语中,构成句型:May+you/n.+动词原形+.*May you have a good journey!祝你旅途愉快！【知识延伸】may well+动词原形,表示“很可能”;may/might as well

9、 do sth.不妨做某事。*He may well be surprised at the result.他很可能会对这个结果感到意外。*To start with,you might as well learn to speak Mandarin.首先,你最好学会说普通话。4.shall(1)shall用于第一、三人称的疑问句中时表示征求意见。*Shall I get you some tea?我给你倒点茶好吗?(2)用于第二、三人称的陈述句时,往往表示给对方(you)或第三者(he,she,they)以允诺、命令、决心、警告或威胁等,在法律、条约、协定等文件中可以表示义务、规定等。*Yo

10、u shall fail if you dont work harder.如果你不再努力点儿,你就会失败。(警告)*Each citizen shall carry his identification card when travelling.旅游时每个市民务必带上身份证。(规定)5.should/ought to(1)表示责任、义务,意为“应该,应当”。*(2020全国卷)I wonder if parents should always tell the truth no matter the consequences.我想知道父母是否总是说出真相,无论结果如何。*(2019全国卷)Yo

11、u should reassess your goals,and motivate yourself to set a fresh goal.你应该重新评估你的目标,并激励自己设立新的目标。(2)should表示惊讶、赞叹或不满,意为“竟然”。*Its strange that he should be late.真奇怪,他竟然会迟到。【即学活用】用适当的情态动词填空。(1)You _ help your mother with the housework.(2)_ you have a happy weekend.(3)It has been announced that candidate

12、s _ remain in their seats until all the papers have been collected.(4)You cant imagine that a well-behaved gentleman _ be so rude to a lady.shouldMayshallshould6.will/would(1)will表示“意愿,意志”,would表示过去时间的“意愿、意志”。*I promise I will do my best to provide best service for the Asian Games.我许诺我会尽最大努力为亚洲运动会提供

13、最好的服务。*I told her to stop crying,but she just wouldnt listen.我告诉她别哭,但是她不愿意听。(2)表示征求意见或提出请求。主要用于第二人称疑问句中,will和would均可用,would此时不表示过去,而是表示委婉语气。*Will/Would you pass me the book?请你把书递给我好吗?(3)will表示某种倾向或习惯性动作,意为“总会,老是”;would表示过去反复发生的动作或过去的一种倾向。*Fish will die without water.没有水,鱼会死去。*When my parents were aw

14、ay,my grandmother would take care of me.我父母外出的时候,祖母总是照看我。【知识延伸】would与used to的区别(1)would表示过去经常性且反复发生的动作,没有与现在对比的含义。*When we were boys,we would go swimming every summer.当我们是孩子的时候,我们每年夏天常常去游泳。(2)used to表示过去经常发生的动作或存在的状态,且现在已终止,强调今昔对比。*People used to believe that the earth was flat.过去,人们总以为地球是扁平的。(现在已不再

15、这样认为)7.need,dare(1)need表示必要性,意为“需要”,dare表示“敢于”;need和dare作情态动词时常用于否定句、疑问句或条件句中,无人称和数的变化,疑问句和否定句中不加助动词。*You neednt come here this afternoon.你今天下午不必来这里。*How dare you say Im unfair?你怎么敢说我不公平?(2)need和dare用作实义动词时,有词形变化。在否定句、疑问句中要加助动词。*You dont need to hurry.You have enough time.你不需要着急。你有足够的时间。*He doesnt d

16、are(to)answer.他不敢回答。【即学活用】用适当的情态动词填空。(1)He _ go to the river nearby to fish on weekends when he was young.(2)Sorry,I forgot to tell John about your party.It doesnt matter.I _ call him in a while.(3)Many people were standing around watching with sympathy,but no one _ to help him up.(4)You _ to get ri

17、d of the habit of drinking cola only.wouldwilldaredneed二、情态动词表推测1.must表示有把握的推测,只用于肯定句中,意为“一定,肯定”。*(2020全国卷)I like eating fried tomatoes with eggs,and I thought it must be easy to cook.我喜欢吃西红柿炒鸡蛋,并且我认为它炒起来一定很简单。*Im sure that you must be concerned about Robert the moment you left for London.我确信你一去伦敦就会

18、很担心Robert。2.can/could表示推测,意为“可能”,用于否定句和疑问句。can比could语气强。*Tom has gone to Beijing,so you cant see him in our school now.汤姆已经去北京了,所以你现在在我们学校看不到他。【名师点津】can表示客观可能性(理论上或是逻辑判断上),意为“可能会”。*It can be rather hot in our hometown in March.在我们家乡三月份可能会很热。3.may/might意为“可能,也许”,指可能性小的猜测。might比may语气更不确定,表示的可能性更小。*He

19、may be at home,but I am not sure.他或许在家,但是我不确定。*(2020全国卷)I tell my mom that if were forced to eat things,we may become ill.我告诉我妈妈,如果我们被迫吃东西,我们可能会生病。4.should表推测,暗含很大的可能,意为“应该,理应”。*Its 4:30.They should be in New York by now.现在是四点半,他们现在应该到达纽约了。【名师点津】情态动词表示推测时,可能性的大小肯定句:mustcan/couldshouldmaymight否定句:can

20、t/couldntshouldnt may notmight not【即学活用】用适当的情态动词填空。(1)It is usually warm in winter in the south,but it _ be cold and even have snow sometimes.(2)Jane _ be very bored with her job.She does the same thing every day.(3)They _ know the answer.Let me explain to them.(4)According to the weather report,it

21、_ rain tomorrow.canmustcantmay三、情态动词+have done情态动词+have donemust have done对过去的肯定推测译为“过去肯定”It must have rained last night,for the road was quite wet.昨晚肯定下雨了,因为路面十分潮湿。cant/couldnt have done对过去的否定推测译为“过去不可能做了”He couldnt have known the decision,but someone told him.他一定不知道这个决定,但是有人告诉他了。could have done本来能

22、够做而没做You could have made greater progress,but you didnt try your best.你本能够取得更大的进步,但是你并没有尽全力。情态动词+have donemay/might(not)have done可能(没有)做过某事You may have dropped it when you were shopping in the market.你或许是在市场买东西的时候(把它)掉了。should(not)/ought(not)tohave done本来该做而没做/本来不该做而做了You should have come to school

23、if you were really serious about your study.要是你真的对待学习认真的话,你本应该来上学的。neednt have done本来不必做却做了You neednt have telephoned him,for he had known the result.你本不必打电话给他,因为他已经知道结果。【即学活用】(1)She _about the explosion.She didnt know anything about it.她不可能读过关于爆炸的消息,她对此一点也不知道。(2)She _the dictionary,but Im not sure.

24、她可能买了那本词典,但我不太确定。(3)I _the umbrella,for the weather is fine.天气这么好,我本没必要带雨伞的。cant have readmay have boughtneednt have taken(4)You _fun of him.He is not the one you laugh at but learn from.你本不应该取笑他。他不是你嘲笑的人,而是你学习的榜样。ought not to/shouldnt have made过去将来时(The past future tense)1.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

25、在的状态,常用在宾语从句中。一般由“would+动词原形”构成。*Then,I realized something terrible would happen.那时,我意识到糟糕的事情将要发生。*My brother told me that he would come back on Saturday.我哥哥告诉我他周六回来。2.was/were going to+动词原形:表示过去将要发生或很有可能发生的动作,常用于口语中,表示预言、意图或者打算等。*I was going to play basketball,but in the end I went to the cinema.我打

26、算去打篮球,但是最后我去看电影了。*He was going to start work the following week.他打算下星期开始工作。3.was/were about to do:常用来表示即将发生的动作,“刚要/正要做”。注意该结构不与任何时间状语连用。*I was about to leave for home when a new task was assigned to me.我正要离开回家,这时我又被指派了一项新任务。4.start,go,come,leave,see,meet等动词的过去进行时,表示就过去某一时刻而言即将发生的动作。*She was coming l

27、ater.她随后就来。*I had just put on my overcoat and was leaving to visit a friend of mine.我刚穿上外套要去看我的一个朋友。5.was/were to do:表示“曾计划做某事”;如果表示“本来计划做某事,动作没实现”,则需用“was/were to have done”。*She said that they were to visit their English teacher the next week.她说他们下周将去看望他们的英语老师。*She said she was to have told me abo

28、ut the accident.她说她本来想告诉我关于事故的事。【即学活用】用所给动词的适当形式完成句子。(1)She said the bus _(leave)at five the next morning.(2)I wasnt sure whether he _(lend)me his book the next morning.(3)At that time he did not know that quitting the job _(become)the turning point in his life.(4)He said he _(visit)China the next w

29、eek.(5)In his introduction,he made it clear that our credit _(be)hard-earned.was leavingwould lendwas to becomewas going to visitwould be【语法主题应用】用适当的情态动词、动词的过去将来时介绍一下你的高考备考情况。1.还有三个月就要高考了,这让我压力很大。2.因为我晚上熬夜,我竟然在课堂上睡着了。3.以往考得不好的时候,我的父母都会安慰我。4.现在我能进行自我调节了。5.我要遵守科学的作息规律。6.祝我在高考中取得好成绩。_ The National Coll

30、ege Entrance Examination will be in three months,whichmakes me under great pressure.Because I stay up late at night,I should fall asleep in class.My parentswould comfort me when I didnt do well in the exam.Now I can adjust myself.Ishall observe scientific work and rest rules.May I gain good results in theNational College Entrance Examination.