单击此处编辑母版标题样式单击此处编辑母版文本样式第二级第三级第四级第五级情态动词Modalverbs一、基本概念：情态动词是表示可能、怀疑、愿望、许诺、猜测等语气的动词。二、情态动词的基本用法情态动词表示说话人的语气和情绪，其本身词义不完整，不能单独作谓语，必须加上动词原形一起才能构成谓语。情态动词没有人称和数的变化（haveto除外），有些情态动词有过去式。常见的情态动词有can,could,may,might,must,haveto,shall,should,will,would,oughtto,need,dare等。含情态动词句型基本结构陈述句：主语+情态动词+动词原形Weshouldstudyhard.一般疑问句：情态动词+主语+动词原形Canyouhelpme?特殊疑问句：特殊疑问词+情态动词+主语+动词原形WhatshouldIdo?考纲情态动词用法详解1、can与could的用法1）.表示能力(could指过去曾经的能力)。Shecanplaychess.Hecoulddrivebefore.2).表示客观上或理论是的可能性。Itcanrainheavilyhere,especiallyinsummer.3).表示请求、建议、允许、许可用could比can语气更委婉,回答用原形。4).表示推测“可能”(用于疑问句和否定句)CouldyoutellmehowIcangettothezoo?Shecan’tbeourheadmaster.ShehasgonetoAmerica.2.may/might1).表示请求、允许、许可,might比may的语气更委婉.—MayIusethecar?—I’mafraidnot.2).表示推测“可能”,could的可能性比can小。ItmightnotbeJane.Shehasn`tdicidedtocomehereyet.3.must1）.表示“必须;应该”Wemustfinishourhomeworkeveryday.2）.表示“一定”ThebookmustbelongtoJim,thereishisnameonthecover.2）.表示“硬要；偏要”Ifyoumustgohome,atleastcallyourmom.4.will/would1）.表示“请求;建议”,用于疑问句。would比will委婉、客气.Will/Wouldyoupleaseopenthewindow?2）.表示意志或意愿Iwillhelpyou.Hepromisedthathewoulddoanythingforyou.3）.表示习惯,will表示现在的习惯,意为“总是;习惯于”。would表示过去的习惯性动作.Thiskindofthingwillhappen.这种事情总是要发生的Hewouldstayuplatewhenhewasyoung.4）.表示“注定会”Fishwilldiewithoutwater.5.shall1).用于第一人称和第三人称的疑问句,表示征求对方的意见.Shallwegooutforawalk?Shallhewaitforyouatschool?  2).用于第二人称和三人称的陈述句,表示“命令、警告、允诺或威胁”.Youshalldoastheteachersays.(表示命令) Youshallreceivemymoneytomorrow.(表示允诺 )  Heshallbesorryforhisbehavioroneday,Itellyou.  (表示警告 )  6.should1)表示劝告和建议,意为“应该”Weshouldhelpeachother.Youshouldbepolitetotheold.2)表示惊讶、意外,作“竟然”讲Tomysurpriseyoushouldnotknowaboutme.3)表示可能性很小,但并非完全不可能，用于if引导的条件状语从句。Ifheshouldbefreeyesterday,hewouldcometoourparty.4）表示推测，意为“想必一定、照说应该、估计”等。Heshouldbefreebynow.  7.oughtto1).表示义务,作“应当”讲,语气比should强烈Asastudent,yououghttostudyhard.Yououghtn’ttospeaksomuch.   2).表示含蓄或不完全肯定的推测,意为“应该”或“应是”Heoughttoknowmytelephonenumber.  8.dare.用于疑问句、否定句和条件状语从句中,表示“敢;敢于”。Shedaren`tgoaloneatnight.Howdareyoucomeagain?Goifyoudare.9.need表示“需要;必要”,用于疑问句、否定句和条件状语从句。Youneedn’tworryaboutme.NeedIgiveyouahand?NeedIhelpyouifyougetintotrouble?容易混淆的情态动词用法区别情态动词主要用法can/could/beabletocan/couldcan只有现在式和过去式(could),表示一般能力beableto用于多种时态，was/wereableto表示曾经通过努力而做成某事Youneedn’tworryaboutme.Youneedn’tworryaboutme.Youneedn’tworryaboutme.情态动词主要用法would/usedtowould表示过去习惯性或重复性的动作,并无跟当前对比之意usedto强调跟现在对比，表示过去经常发生的动作或存在的状态,表明“现在不再以前那样了”情态动词后面跟完成时情态动词+havedone的用法1.对过去的推测1).musthavedone表示对过去已经发生的行为进行推测,意为“准是、想必、一定做了某事”,通常用于肯定句。Youmusthavegoneswimming,foryourhairiswetnow.2).mayhavedone和mighthavedone也许、或许、已经表示对过去所发生动作的推测,常用于肯定句或否定句。I’mnotsure.Hemighthaveinvitedyou.3).canhavedone和couldhavedone表示对过去所发生动作的怀疑和否定,通常用于否定句和疑问句WherecanTomhavegone?IsawLiLinplayingfootballjustnow.Hecouldn’thavebeenill.2.表示遗憾、后悔或责备1).shouldhavedone和oughttohavedone用于肯定句表示“本该做某事,而实际上没有做”Youshouldhavegivenherahandjustnow.用于否定句表示“本来不该做的事反而做了”。Yououghtn`ttohaveinvitedhim.2).mighthavedone用于肯定句,表示本应该或可以做某事,带有轻微的责备的语气。Youmighthavehelpedyourmotherwithhousework.3).couldhavedone本来可以……常用于肯定句,表示过去没有实现的可能性。Youcouldhavepassedtheexam,butyouweretoocareless.4).needn`thavedone用于否定句表示过去“本来不需要……”Youneedn’thaveworriedaboutme.   你本不必为我担心。情态动词后面跟进行时情态动词+be+doing表示“想必正在……”，“可能正在……”，“应当正在”Theymaybediscussingourproblem. Shecan’tbetellingthetruth. TheymustbechattingontheInternet.  Youshouldn’tbeworkinglikethis. EXERCISES一、用适当的情态动词填空1.Youworryaboutme.needn’t2.Helookssopale,hebeill.must3.Plantsdiewithoutsunshine.will4.TheredcoatbeBob`s,hedoesn`tlikeredatall.can’t.5.Welearnfromeachother.6.MissLihelpmewhensheworkedatourschool.7.Hecometoseeyouagain.8.Wehelpparentswithhousework.shouldwoulddaren’toughtto二、单项选择：1.Youfailintheexamwithouthardworking.A.willB.wouldC.mustn‘tD.can2.Hehadtogiveupsmokingbecauseofhisillness,he?A.didB.doesC.didn’tD.doesn‘t3.—MayIwearjeanstotaketheparty?—Sorry,you,youshouldwearasuit.A.needn'tB.can'tC.maynotD.mustn't4.Let`stakeawalk,we? A.canB.wouldC.mustD.shallACBD5.Idon`tknowifhe playtheguitarbefore.A.would B.could   C.did  D.had6.Theregoesthebell,We'dbetterspeak. A.notB.nottoC.won'tD.don't7.Studentstelllies.A.maynotB.mustC.canD.mustn`t8.We  followtheruleshere.A.canB.mayC.ought toD.couldBADC9.Youwakenmeup,it`sSundaytoday.A.needn’thaveB.musthaveC.needhaveD.mustn`thave10.I hope that everyone passtheexam.A.canbeabletoB.willbeabletoC.wouldbeabletoD.areableto11.—Don'teatinclass.—______A.Yes,Iwon't.B.Sorry,Ican't.C.Sorry,Iwon't.D.OK,Ididn't.ABCTHEEND!THANKYOU!