【课件】Unit+5+Discovering+Useful+Structures+课件人教版（2019）必修第三册

DiscoveringusefulstructuresUnit5TheValueofMoneyTheyarecalledmodalverbs.情态动词没有人称和数的变化，即不随主语的不同而变化。情态动词不能独立作谓语，须后接动词原形一起构成谓语动词。情态动词的特点LeadingA.The

exam

may

be

difficult.a.The

exam

is

difficult.B.You

should

be

studying

harder.b.You

are

studying

harder.C.I

canstudy

all

night

during

thesemester.

c.I

study

all

night

during

the

semesterReadthefollowingsentences.Focusonthemodalverbsandtrytofindthedifferentmeaningsofeachgroupofsentences.Summary1:Thefunctionofmodalverbsistoexpressmodality./məʊˈdæləti/People'sfeelingandattitudeExampleNecessityPossibilitiesObligationRequestAdviceIntentionWecandiscussitnow.Youmustdoitatonce.Wouldyoupleasepassmethesalt?Youneedn’thavestayed.Yououghttohelphim.Iwouldratherdoitmyself.需要可能或推测职责/义务请求建议意图和愿望Readthefollowingsentencesandtrytochoosewhatthemodalverbsexpress.Summary2:Modalverbscanbeusedtoexpressnecessity,possibility,obligation,request,adviceandintention.Analyzewhatthemodalverbsexpress.1.HenrymustbeanAmerican.2.HenrycanbeanAmerican.3.

HenrycouldbeanAmerican.4.HenrymaybeanAmerican.5.HenrymightbeanAmerican.PossibilityModalverbsusedtoexpresspossibility:must,can,could,may,mightDegreeofpossibilityHighLowAnalyzewhatthemodalverbsexpress.1.Youmustcomeatonce.2.Wehavetowearuniformsatschool.3.Ioughttobeonmyway.Necessity&ObligationModalverbsusedtoexpressnecessity&obligation:

must,haveto,oughttoAnalyzewhatthemodalverbsexpress.1.Willyoupleasetakehertothelibrary?2.Couldyouoffermeworkhere?3.CanIaskaquestion?4.Mayweaskwhatyou'redoinginthiscountry?5.Wouldyoupleasepassmethesalt?RequestModalverbsusedtoexpressrequest:

will,could,can,may,wouldAnalyzewhatthemodalverbsexpress.1.Henrymustacceptthebanknote.2.Henrycouldacceptthebanknote.3.Henrycanacceptthebanknote.4.Henryhad

betteracceptthebanknote.5.Henryshould/oughttoacceptthebanknote.AdviceModalverbsusedtoexpressadvice:

could,should,oughtto,hadbetter,canStrongerWeakerAnalyzewhatthemodalverbsexpress.1.Youmustn'tsaythingslikethat.2.Youcan'topenituntiltwoo'clock.3.Youshouldn'ttakeherhelpforgranted.NegativeadviceModalverbsusedtoexpressnegativeadvice:mustn't,can't,shouldn'tAnalyzewhatthemodalverbsexpress.1.Wouldyourecommendtheplaytootherpeople?2.Iwouldliketoknowthedate.3.I'dlovetogotoyourbirthdayparty.4.I'drather

notpay

younow.IntentionModalverbsusedtoexpressintention:

would,wouldliketo,wouldloveto,wouldratherReadthepassageandfillintheblankswithsuitablemodalverbsinthebox.maymustcanoughttomighthadbetterwouldshouldInthefilmTheMillionPoundBankNote,HenryAdamsisstuckinaforeigncountrywithoutmoneyandfriends,andwithnowheretostay.Whilethissituation_____seemunusual,itcansometimeshappentotravellers.Incaseithappenstoyouonatripabroad,what______youdo?First,andmostimportantly,you_____staycalm.Fear____causeyoutobecomeconfused.Youneedtothinkclearly.Second,youshouldgotoyournearestconsulate.They________beabletohelptosomeextent.Third,you______dowelltocheckwithsomelocalcharities.They______offerhelptotravellersinneed.Fourth,you_________avoidgettingintotrouble.You______thinkthatstealingsomemoneyorfoodwouldhelpyou,butyoushouldnotdoso.Gettingcaught______ruinyourlife.mayshouldmustcanoughttowouldmighthadbettermightwould1.may&

might

①—MayIwatchTVaftersupper?—Yes,youmay/can./No,youcannot/mustn’t.②Theymay/mightbehavingameeting,butI’mnotsure.③Ifthatisthecase,youmay/mightaswelltry.①句中may表示______________________。

否定回答时，用_______________。(2)②句中may和might表示_________，______可能性更小。(3)③句中______________________________,意为“不妨”允许或征询对方许可cannot/mustn’t可能性mightmay/mightaswell＋

动词原形may

表示祝愿;但语气较正式:

May

yousucceed!

May

youhaveagoodjourney!

might

多在间接引语中表示过去的可能和允许。

Shesaidthathemighttakeherbike.

考点①IhavetowaitherebecauseIhavenoumbrellawithme.②Imustrecitethetextthismorning.③—Mustwehandinourexercisebookstoday?—Yes,youmust./No,youdon’thaveto/youneedn’t.④Youmustn’tsmokehere.⑤Yourmothermustbewaitingforyounow.⑥Whymustyoualwaysinterruptme?(1)①句中haveto和②句中must均表示“______”，但______是指说话人的主观看法，而________则强调客观需要。(2)③句中must所构成的疑问句，回答的否定形式通常为__________________或________，意为“不必要”，而一般不说____________(④句中mustn’t表示“禁止”)。2.must&haveto必须musthavetoneedn’tdon’thavetomustn’t1.在一、三人称的疑问句中,shall用来询问对方的意愿。

Whatshallwedothisweekend?2.用于二、三人称的陈述句中,表说话人命令、警告、允诺等口吻。

Youshallfailifyoudon’tworkhard.(警告）Heshallbepunished.(威胁）3.should表示劝告、建议、命令，用于各种人称。

Weshouldtrytosavewaterinsuchterribleweather.4.should表示说话人的惊讶、愤怒、失望等特殊情感，意为“居然，竟然”。

It'sstrangethatheshouldcomesolate.Heshouldhavebeenmorecarefulintheexam.You

shouldn’thavetold

herthenews.

shouldhavedone表示本该做某事（而实际上未做）

shouldn'thavedone表示本不该做某事（而实际上做了）3.shall和should①Ifhedarego,I’llgowithhim.②Tomdidn’tdare

todoit.(1)dare作情态动词时，表示“__________”。常用于否定句和疑问句中，后接动词原形，否定形式为_________。(2)dare常用作_________，有________________的变化，后面可接________________

。(3)dare作为实义动词，有如下搭配：

daretodosth

敢于做某事

daresb

todosth

激某人做某事 4.dare敢；

敢于darenot实义动词时态、人称和数带to的不定式1．need作情态动词时，后跟动词原形，表示“需要，有必要”，无时态、人称和数的变化，多用于否定句、疑问句或条件句中。5.need的用法Youneedn'ttellhimaboutitthisafternoon.2．由need引出的一般疑问句的肯定回答常用must或haveto，而否定回答则常用needn't或don'thaveto。—NeedIgonow?—Yes,youmust./No,youneedn't.今天下午你不必把此事告诉他。3.need还可作实义动词，此时有人称、时态和数的变化，后面接带to的动词不定式。常用的结构有两个：need的用法(1)sb.need(s)todosth.意为“某人需要做某事”(2)sth.need(s)doing/tobedone意为“某事/某物需要被……”doing用主动形式表示被动，sth.是do所表示动作的承受者。明天我需要早起。我的自行车需要修理。Ineedtogetupearlytomorrow.Mybikeneedsrepairing/toberepaired.PracticeCompletethefollowingsentencesusingmodalverbs.You’vebeenworkingdayandnight.You______beverytired.2.—Iwonderwhothatisatthegate.

—It_____beLisa.She’salwaysinthelibraryatthistime.3.Itisalongtimesincewemetlastspring.You_______oftencometoseeusthaneverbefore.4.Hehasn’tdecidedwherehe’sgoingformyholidays.He_____gotoAustralia.5.Father’sDayiscoming.Whatkindofgift_____Igettomyfather?6.Whydon’tyoutryonthisdress?It_____lookniceonyou.7.—Whowasthemantalkingwithyourteacher?—I’mnotsure.It______beherbrother.mustcan’tshouldmayshallwillmight过去将来时(ThePastFutureTense)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。过去将来时句子中有时包含时间状语thenextday,soon等。3.Completethefollowingsentencesthatdescribethefutureusingeitherformofthegivenverbs.1.PhilipboughttwoticketsforThePhantomoftheOpera.He_____________________________(watch)withhisgirlfriendontheweekend.2.IwassosurprisedatthenewsthatDavid___________________________(play)theroleofthedinosaurintheplaythatIgavehimahugoutofjoy.3.Lilydecidedthatshe____________________________(settle)inNewYorkandpursueherdreamofbecominganactress.4.Hey,Timmy.I________________(call)you.Butnowthatyouarehere,Idon’thaveto.5.Thecompetitionwassoclosethatnoonewassurewho___________(win)

theBestActoraward.6.Jimisnothererightnow.Hesaidhe_______________________