高中英语语法-《情态动词与虚拟语气》教学案

一、情态动词的语法特征

(1)情态动词不能表示正在发生或已经发生的事情，只表示期待或估计某事的发生。

(2)情态动词除ought和have外，后面只能接不带to的不定式。

(3)情态动词没有人称，数的变化。

(4)情态动词没有非谓语形式，即没有不定式、分词、动名词等形式。二、虚拟语气用来表示说话人的主观愿望或假想，所说的是一个条件，多半不是事实，或与事实相反。高考重点要求：1、情态动词的基本用法2、情态动词表示推测的语义差别3、情态动词后接不定式完成体的不同意义4、虚拟语气中情态动词的用法情态动词(一)情态动词在一般时否定句中的用法can't(cannot)表示“不可能”，maynot表示“不可以”“可能不”，mustn't(mustnot)表示“一定不要”，“不许可”，needn't(neednot)表示“不必”，darenot＋动词原形表示“不敢”。Hecan'tknowthenews.Hemaynotsleepnow.Youmustn'tcriticizeherinthatway.Youneedn'tcometomorrow.Hedarednotmeethisparents.（二）can，may，must三者用法比较can，may，must是三个最重要的情态动词1.can，may，must的肯定句Youmayeatlunch，butyoumustwashyourhands.你可以吃饭，但是你必须洗手。（1）can表示能力；能，会Shecanrunfast，butIcan't.她很会跑，但是我不会。表示可能；能够Icangetthereintenminutes.我十分钟之后就可以到那儿。（表示一种可能性）表示允许；许可Youcanusethisdictionary.你可以用这本字典。can和beableto比较can只有现在式和过去式，而beableto可以用于各种时态。can（could）表示能力时，可用beableto代替。Ican（=amableto）payforthebook.

我买得起那本书。Hewillbeabletotellyouthenewssoon.

他很快就能告诉你消息了。Shehasbeenabletocometoschool.

她已经能去学校了。（2）may表示请求、许可MayIborrowyourpen？我可以借你的钢笔用一用吗？可能、或许TomorrowImaygoshopping.明天，我可能（或许）去商店买东西。Hemightbeournewteacher.他或许是我们的新老师。（3）must必须、应该（表示有做某一动作的必要或义务）Youmustbuyaticket.你必须买一张票。一定、准是（表示有把握的判断或推测，一般只用于肯定句中）Hemustbeournewteacher.他肯定是我们的新老师。表示推测的用法can,could,may,might,must皆可用来表示推测，其用法如下：could,might表示推测时不表示时态，其推测的程度不如can,may。can,could用于否定句和疑问句中。句型：主语+can't,couldn't+be+v-ing．（否定句）Can,Could+主语+be+v-ing．（疑问句）Theycan'tbecleaningtheroomnow．他们现在不可能在打扫房间。may,might,must用在肯定句中。句型：主语+may,might,must+be+动词-ing（表示对现在发生动作的推测）Hemustbesleeping.他现在肯定在睡觉。must/can't…+have+过去分词则指对过去已发生的事进行推测。Theroadiswet.Itmusthaverainedlastnight.地是湿的；昨天晚上肯定下雨了。Thereisn'tanywaterontheroad.It(can't)couldn'thaverainedlastnight.Youmusthaveseenthefilm,______________you?(三)haveto的用法1.have（has）to+动词原形have（has）to后面要用动词原形。当主语为第三人称单数时用hasto，当句子是过去时用hadto。Wehavetoleavenow.HehastoworkonSunday.IhadtodomyhomeworklastSunday.2.haveto的否定句句型：主语+don't（doesn't,didn’t,willnot）haveto+动词原形Youdon'thavetowalksofast.Hewillnothavetobuyanewcoatnextyear.3.haveto的疑问句你现在必须学数学吗？___________________________________________.Yes，I__________________.No，I________________（haveto）。他非要问那个问题吗？Didhehavetoaskthequestion？Yes，hedid.No，hedidn't（haveto）4.must与haveto比较must侧重于个人意志和主观上的必要，haveto侧重于客观上的必要。如果用于过去时态或将来时态时，则要用haveto的相应时态来代替must。但must可用于间接引语中表示过去的必要或义务。Mybrotherwasveryill，soI_____________callforthedoctorinthemiddleofthenight.Ihaven'tgotanymoneywithme，soI'llhavetoborrowsomefrommyfriend.Hesaidthatthey__________workhard.他说他们必须努力工作。(四).usedtodosth的用法注意其否定句和疑问句的结构。Thereusedtobealotoftreeshere,____________________?虚拟语气虚拟语气表示说话人的意愿、假设、猜测或建议。虚拟语气不表示客观存在的事实，谓语动词用特殊的形式表示虚拟语气。一、掌握虚拟语气的四种主要形式（1）条件从句+主句（2）几个常用虚拟语气的句型（3）wish,asif及ifonly的虚拟形式（4）Itistimethat的虚拟形式二、注意虚拟语气的三种活用现象（1）含蓄条件句（2）时间错综句（3）虚实错综句条件从句+主句时间谓语动词的虚拟形式从句主句现在动词过去式（be多用were）would/should/could/might+动词原形过去had+过去分词would/should/could/might+have+过去分词将来动词过去式或should/wereto+动词原形would/should/could/might+动词原形1.Therice______ifyouhadbeenmorecareful.A.wouldnotbeburningB.wouldnotburnC.wouldnothaveburntD.wouldnotburnt2.Ifmylawyer____herelastSaturday,he______mefromgoing.A.hadbeen;wouldhavepreventedB.hadbeen;wouldpreventC.were;wouldpreventD.were;wouldhaveprevented3.Ididn’tseeyoursisteratthemeeting.Ifshe______shewouldhavemetmybrother.A.hascomeB.didcome C.cameD.hadcome4.______forthefreetickets,Iwouldnothavegonetothefilmssooften.A.IfitisnotB.WereitnotC.HaditnotbeenD.Iftheyhavenot5.Youdidn’tletmedrive.Ifwe______inturn,you______sotired.A.drove;didn’tgetB.drove;wouldn’tgetC.weredriving;wouldn’tgetD.haddriven;wouldn’thavegot6.Ifshehadworkedharder,she______.A.wouldsucceedB.hadsucceededC.shouldsucceedD.wouldhavesucceed7.—Ifhe______,he______thatfood.—Luckilyhewassenttothehospitalimmediately.A.waswarned;wouldnottakeB.hadbeenwarned;wouldnothavetakenC.wouldbewarned;hadnottakenD.wouldhavebeenwarned;hadnottaken8.Ifit______tomorrow,theywouldnotgotherebybike.A.willrainB.rains C.wouldrainD.shouldrain9.______itraintomorrow,wewouldhavetoputoffthevisittotheYangpuA.WereB.Should C.WouldD.Will10.IfI______you,Iwouldnotdoit.A.amB.were C.shallbeD.being（一）、含蓄条件句含蓄条件句就是虚拟条件暗含在短语或上下文中，从句不表现出来。这时，必须根据句中表述的意义以及某些特定的信息词，并依据前文所列举的四种现象，来判断此时须采用的形式。1.Withoutelectricity,humanlife______quitedifferenttoday.A.isB.willbeC.wouldhavebeenD.wouldbe2.YesterdayJanewalkedawayfromthediscussion.Otherwise,she______somethingshewouldregretlater.A.hadsaidB.saidC.mightsayD.mighthavesaid（二）、时间错综句从句与主句或上下文所表述的时间不一致。在这种情况下，我们切不可照搬某种形式，而应该按照句中所表述的时间关系，再选择相应的虚拟形式。例如：Ifyouhadworkedhardyesterday,youwouldbetirednow.1.Iftheflowerhadbeenwatered,it______now.A.wouldn’tdieB.isdeadC.hadbeendeadD.willnotdie2.Ifhistelevisionsethadnotbeenstolenyesterday,he______TVnow.A.wouldwatchB.wouldhavewatchedC.wouldbewatchingD.iswatching几个常用虚拟语气的句型1.动词+宾语从句一个坚持：insist;两个命令：order,command;三个建议：suggest,propose,advise;四个要求：desire,demand,ask,requireIproposethatwe(should)setadeadlineforhandingintheplans.Isuggestthatwe(should)setoffatonce.Iinsistedthatwe(should)decidewhattodowithhim.虚拟语气形式：(should)+动词原形2.Itis(was)+上述动词的过去分词+that主语从句Itisdemandedthathe(should)leaveatonce.Itisrequestedthatshe(should)giveaperformanceattheparty.3.Itis(was)+important/necessary/better/strange/surprising/natural/possible/apity/nowonder+that主语从句Itisbestthathe(should)setoffatonce.Itisimportantthateverybody(should)betoldallthefacts.虚拟语气形式：(should)+动词原形4.order等+be+表语从句Myadviceisthatwe(should)sendforadoctor.Oursuggestionisthatyou(should)befirsttogo.Hisonlyrequestisthatyou(should)givehimmoretime.5.order等+同位语从句Doyouknowtheorderthatyou(should)keepwatch?上述结构中常用的名词有：suggestion,order,proposal,plan,idea,command,request等。虚拟语气形式：(should)+动词原形1.Iinsistthatadoctor______immediately.A.hasbeensentforB.sendsforC.willbesentforD.besentfor2.Itissuggestedthatthejob______doneinanotherway.A.wasB.wastobeC.beD.mustbe3.Hehadanideathatwe______bybike.A.shallgoB.goC.wentD.wouldgo4.Mysuggestionisthatthemeeting______offtilltomorrow.A.toputB.beputC.shouldputD.beputting5.Theyoungmaninsistedthathe_____nothingwrongand_____free.A.did;setB.haddone;shouldbesetC.do;besetD.does;wouldbeset6.Itisnecessarythatyou______presentatthediscussion.A.willbeB.areC.shouldbeD.wouldbe7.Thebossgaveordersthatthework______atonce.A.willbestartedB.mustbestartedC.bestartedD.shouldstart8.Theguardthereinsistedthateverybody______therules.A.obeysB.obeyC.willobeyD.wouldobeywish,asif以及ifonly的虚拟形式：这几个词（词组）表虚拟时，其后所用的虚拟形式与条件从句基本相同，即此陈述语气中的时态后退一个时态。随“时”变化的几种用法：

时间谓语动词虚拟语气wish/asif/asthough/ifonly/wouldrather现在动词过去式（be多用were）过去had+过去分词将来would+动词原形1.IwishI______youyesterday.A.seenB.didseeC.hadseenD.weretosee2.Whenapencilispartlyinaglassofwater,itlooksasifit______.A.breaksB.hasbrokenC.werebrokenD.hadbeenbroken3.I’dratherthatyou______thereyesterdayand______againnextweekend.A.went;shouldcomeB.shouldgo;hadcomeC.hadgone;cameD.go;come4.Thetwostrangerstalkedasifthey______friendsforyears.A.shouldbeB.wouldbe C.havebeenD.hadbeen5.—Iblamedheryesterday.—Iwouldratheryou______that.A.didn’tdoB.hadn’tdone C.wouldn’tdoD.shouldn’tdo6.—Heisaverybraveman.—Yes.IwishI______hiscourage.A.have B.had C.willhaveD.wouldhaveItistimethat的虚拟形式Itistimethat…Itishightimethat…Itisabouttimethat…Itistime还可以有其他句型形式，需注意辨析：Itistime(forsb.)todosth.Itistimeforsth./doingsth.Itisthefirsttimethat(从句用陈述语气的现在完成时)1.Itishightimeyou______thebus.A.hadcaught B.caughtC.willcatch D.catch2.It’sabouttimehe______todothework.A.begins B.willbeginC.begin D.began3.It’shightimethatwe___toschool.A.wouldgo B.wentC.go D.willgo4.Itistimewe___upourresults.A.sum B.summedC.willsum D.wouldsum巩固练习1.—Isn'tthatAnn'shusbandoverthere?—No,it_______behim.I'msurehedoesn'twearglasses.A.can't

B.mustnot C.won't

D.maynot2.Youtothemeetingthisafternoonifyouhavesomethingimportanttodo.A.needn'ttocome B.don'tneedcomeC.don'tneedcoming D.needn'tcome3.Heyoumorehelp,eventhoughhewasverybusy.A.mighthavegivenB.mightgiveC.mayhavegivenD.maygive4.Thereasonwhytheyleavewasn'texplainedtous.

A.had B.hadto C.must D.might5.Isearchedformywalletanditwasn'tthere.IthoughtIitathome.

A.left B.haveleft C.mighthaveleft D.couldhaveleft6.I________asleepbecauseittookmealongtimetorealizethatthetelephonewasringing.

A.couldhavefallen B.shouldhavefallenC.musthavefallenD.mustn'thavefallen7.Theonlythingthatreallymatterstothechildrenishowsoontheyreturntotheirschool.

A.can B.must C.haveto D.oughtto8.Iwanttogotothechemist's,butyougowithme.

A.neednot B.mustnot C.need D.can’t9.Whatwegetseemsbetterthanwhatwehave.

A.can B.could C.can't D.couldn't10.—Mygoodness!I'vejustmissedthetrain.—That'stoobad.Iamsureyouit,ifyouhadhurried.A.couldhavecaught B.hadcaughtC.wouldcatchD.couldcatch11.Look!Whatyou'vedone!Youmorecareful.

A.maybe B.hadto C.shouldhavebeen D.wouldbe12.Irepeatthequestion?

A.Shall B.Will C.Doyouwantthat D.Do13.ProfessorLi,manystudentswanttoseeyou.theywaithereoroutside!

A.Do B.Will C.Shall D.Are14.Youreadthatbookifyoudon'twantto.

A.haven't B.can't C.mustn't D.needn't15.Johnny,youplaywiththeknife;youhurtyourself.

A.won't…can't B.can't…shouldn'tC.shouldn't…mustD.mustn't…may16.—Therewerealready5peopleinthecar,buttheymanagedtotakemeaswell.—Itacomfortablejourney.

A.can'tbe B.shouldn'tbe C.couldn'thavebeen D.mustn'thavebeen17.Tomoughtnottomeyoursecret,buthemeantnoharm.

A.havetold B.tell C.betelling C.havingtold18.Everyoneishere.westartthemeeting?

A.Can B.Must C.Should D.Shall19.Iparkedmycarrightherebutnowit'sgone.It.

A.mustbestolen B.maybestolen

C.musthavestolen D.musthavebeenstolen20.Hetheworkyesterday,buthedidn't.

A.musthavefinished B.needhavefinishedC.finishedD.shouldhavefinished21.Hedidnotpasstheexamination.Asagoodstudent,he.

A.mustn'thavefailed B.maynothavefailedC.needn'thavefailedD.shouldn'thavefailed22.itbetruethatAlbertpassedthetestingeography?

A.May B.Should C.Could D.Would23.Youleadahorsetothewaterbutyounotmakeitdrink.

A.will…can B.may…can C.may…dare D.dare…can24.—Mustwefinishthecompositioninclass?—No,you.

A.needn't B.mustn't C.won't D.shouldn't25.Hereyeswerered.She.

A.mustcryB.mustbecriedC.musthavebeencryingD.maycry26.Maryhisletter;otherwiseshewouldhaverepliedbeforenow.

A.hasreceivedB.mustreceiveC.couldn'thavereceivedD.shouldn'thavereceived27.ItoldSallyhowtogethere,butperhapsIforher.

A.hadtowriteitoutB.musthavewrittenitoutC.shouldhavewrittenitoutD.oughttowriteitout28.Hedescribedthetownasifheithimself.

A.hadseen B.hasseen C.saw D.sees

29.Mostinsuranceagentswouldratheryouanythingaboutcollectingclaimsuntiltheyinvestigatethesituation.

A.do B.don’t