Unit5DiscoveringUsefulStructures課件-高一英語人教版（2019）必修第三冊

DiscoveringusefulstructuresinB3U5Leading-inMayweaskwhatyou'redoinginthiscountryandwhatyourplansare?Ican'tsaythatIhaveanyplans.Youmustn'tworryaboutthat.Couldyouoffermeworkhere?Readthesentencesbelowandthinkabout:Whatarethefunctionsandmeaningsofthesemodalverbs?A.necessityB.possibilityC.obligationD.requestE.adviceF.intentionThefunctionsofmodalverbsYouhavetoreadbetweenthelinesbecausetherealmessagesareoftenhidden…Itmayseemluckytoyou.Astronautsmustwearspacesuitswhentheyworkinspacebecause…

Mayweaskwhatyou’redoinginthiscountry?Youshould/oughtto/hadbettergotoclassrightaway.Whatwouldyoudoifyouwereinhersituation?necessity表必要性possibility表可能和推測obligation表義務性request表請求或指示advice表建議intention表意圖和愿望A.necessityB.possibilityC.obligationD.requestE.adviceF.intention情態(tài)動詞情態(tài)動詞有一定的意義，表示或暗示某種情緒或態(tài)度，表示可能、建議、愿望、必要、允許、能力等。大多數情態(tài)動詞有多個意義。2.情態(tài)動詞沒有人稱和數的變化，即不隨主語的不同而變化。3.情態(tài)動詞不能獨立使用，須后接動詞原形，一起構成謂語動詞。4.情態(tài)動詞除ought和have外，后面接不帶to的不定式。(dare)5.情態(tài)動詞沒有非謂語形式，即沒有不定式、分詞等形式。Reviewofmodalverbs1.只作情態(tài)動詞的：2.可情態(tài)可實義的：

3.可情態(tài)可助動詞的:

4.相當于情態(tài)動詞的:

情態(tài)動詞的分類can/could,may/might,oughtto,mustneed,dare/daredshall/should,will/wouldhaveto,usedtocan&could能力，猜測，請求,許可Someofuscanusethecomputernow,butwecouldn’ttenyearsago.Youcanhavemyseat.Iamgoingnow.Could

Ihaveadrinkofwater,please?Canhestillbealiveafterallthistime?Ifyou’renotcareful,youcouldgetintoevenworsetrouble.能力許可請求猜測猜測could表請求，比can更委婉。Could表推測的可能性比can小can/couldhavedone

can’t/couldn’thavedoneYou_______________(have)abettermarkifyouwentoverthevocabulary.Isawhimjustnow,sohe___________________(go)abroad.couldhavehadcouldn’tbeengone本可以否定猜測注意can的慣用語Onhearingthestory,Icannothelplaughing.Youcannotbetoocarefulwiththem.Youcan’tbecarefulenough.cannothelp+動名詞忍不住做某事cannottoo/enough“無論怎么樣..也不為過,越…越好”

may和might

MayIhavealookatyourbook?Youmayusemaydictionarysolongasyoureturnitbefore7:00.Hemaybewaitingforyouatthestation.Theymayhavegotlost.可能性許可請求may/mighthavedone過去的猜測當句中出現“Iamnotsure”等表示不確定含義的時候,常選用may和might.I___(may/can)go,butIamnotquitesure.可能性：can>

could>

may>

might1.對may的一般疑問句的肯定回答可用may或can,但作否定回答時要用mustn't或can't?！狹ay(Might)Ihavealittlebrandy?—No,youmustn't.You'dbetternot.2.May可以表示祝愿或希望，而might不行。Maytheybeveryhappyinthefuture.Mayyousucceedinthecomingyear.will和wouldAsk,ifyouwill,whotheowneris.MyfriendaskedifIwould

gowithhim.Will/Wouldyoupleasehaveacoffeeforme?Thiskindofclothes

won’t

washeasily.That’sjustlikeher—shewouldloseherbaginthebus!意愿過去的意愿請求習慣would比will客氣委婉Iwill

tellyousomethingimportanttomorrow.Willyoumarryme?（助動詞）

（情態(tài)動詞）1.在一、三人稱的疑問句中,shall用來詢問對方的意愿。Shallwebeginourlesson?2.用于二、三人稱的陳述句中,表說話人命令、警告、允諾等口吻。HeshallhavethebookwhenIfinishreading.shall和shouldYoushouldbepolitetoyourteachers.3.should表示勸告、建議、命令，用于各種人稱。4.should表示說話人的驚訝、憤怒、失望等特殊情感，意為“居然，竟然”。Amazing!Youshouldwearslippersatwork.1.Youshouldhaveaskedforsomehelp.2.You

shouldn’thavetold

herthenews.

shouldhavedone表示本該做某事（而實際上未做）

shouldn'thavedone表示本不該做某事（而實際上做了）must:肯定句表有把握的推測:“一定”。2)must:推測現在或正發(fā)生的事情：mustbedoing，

eg:他現在肯定呆在那里。Hemustbestayingthere.3)must推測已經發(fā)生的事：musthavedone

Ididn'thearthephone.I_______________________(我剛才沒有聽到電話，我想必是睡著了。)

musthavebeenasleep如何表示否定的猜測？can’teg:Shecan’thaveleftschool,forherbikeisstillhere.mustmust用于一般疑問句中,肯定:must否定:

needn’t/don’thaveto（不必），mustn’t表示“禁止，不允許”

—Must

I

finish

all

assignments

at

a

time?

—Yes,you______.No,

you___________

.mustneedn't/don’thavetoPracticeCompletethefollowingsentencesusingmodalverbs.You’vebeenworkingallday.You______beverytired.2.—Iwonderwhothatis.

—It_____beLisa.She’sinthelibraryatthistime.3.Itisalongtimesincewemetlasttime.You__comeandseeusmoreoften.4.Ihaven’tdecidedwhereI’mgoingformyholidays.I_____gotoAustralia.5.Myfather’sbirthdayiscoming.What_____Igethim?6.Whydon’tyoutryonthisdress?It_______lookniceonyou.7.—Whowasthemantalkingwithyourteacher?—I’mnotsure.It______beherbrother.8.Idon’tknowwhentheguestsbehere.They_________arriveatanytime.mustcan’tshouldmayshallwillmightwill/could過去將來時(ThePastFutureTense)過去將來時表示在過去某一時間將要發(fā)生的動作或存在的狀態(tài)。過去將來時常用在主句謂語動詞為過去時態(tài)的賓語從句中。過去將來時句子中有時包含時間狀語thenextday、soon等。過去將來時，表示從過去某一時間來看，將要發(fā)生的動作或存在的狀態(tài)。1.IaskedhimifPeterwouldarrivethenextday.2.Shetoldmeshewasgoingtoposttheparcel.3.Wewereabouttogotherewhenitbegintorain.4.Shedidn'tsaywhenshewascomingagainnexttime.5.IfeltnervousbecauseIwassoontoleavehomeforthefirsttime.6.Weweretohavebeenmarriedlastyear.1.would/should+動詞原形2.was/weregoingto+動詞原形*與would+動詞原形相比，was/weregoingto+動詞原形有打算、計劃的含義。3.was/wereabouttodo4.go,come,leave,start,meet等動詞的過去進行時，表示就過去的某一時刻而言即將發(fā)生的動作。5.was/weretodo;表示曾經計劃做某事，并且從現在看已經實現。當表示“原計劃做某事但是最終未發(fā)生”，用was/weretohavedone.Completethefollowingsentencesthatdescribethefutureusingeitherformofthegivenverbs.1.PhilipboughttwoticketsforThePhantomoftheOpera.He_____________________________(watch)withhisgirlfriendontheweekend.2.IwassosurprisedatthenewsthatDavid___________________________(play)theroleofthedinosaurintheplaythatIgavehimahugoutofjoy.3.Lilydecidedthatshe_______________