情态动词只有情态意义

情态动词只有情态意义,即它所表示的是说话人对动作的观点，如需要、可能、意愿或怀疑等。情态动词的特征：.在形式上，情态动词没有实义动词的各种变化。.在意义上,大多数情态动词有多个意义。3.在用法上，情态动词与助动词一样,须后接动词原形。情态动词各自的基本意义及用法一、can与could用法对比表对比点cancould1、表“能力"Canyouliftthisheavybox?Icouldn'tunderstandwhathesaidatall.2、表"许可"Youcanuseadifferentmaterialinstead.HesaidIcouldborrowhisbike.3、“怀疑"No,no,itcan"tbetrue.Whatonearthcanthismean?Wethoughtthestorycouldnotbetrue.Howcouldyoubesocareless?4、can与beableto区别1.could代替can,表示语气更为婉转。Eg.CouldIuseyourbike?Yes,youcan.2.can（能够）=beableto（仅表能力时），但beableto表示一番努力后,才能做得到，且有更多的时态。Hewasagoodswimmer,soheswimtotheriverbankwhentheboatsank.couldmightshallwasableto二、may与might用法对比表对比点mayMight.表“询问"MayI-?（=CanI•••?）MightI-?（=CouldI…?）（但比用may更客气）1.表"允许“Youmaytaketheboythere.Hetoldmehemightcome.（might与told相呼应）.表"可能""或许"Shemaynorlikethisplace.I'mafraidhemightnotlikethisplay.注：1.MayI…？的答语。may可表示期望或祝愿Mayyousucceed!may（might）用于目的状语从句中肯定:Yes,youmay.否定:No,youmustn*t不行（语气强硬）No,youmaynot或No,you'dbetternot.Theemperorgavethemsomegoldinorderthattheymightbegintheirworkatonce.三、must与haveto的用法对比表对比点musthaveto.表“必须”（主观看法）必须;没有过去式,可用于间接引语中。Hetoldme1mustdoaccordingtowhathesaid.（客观需要）不得不，有多种时态。It'srainingheavily,wecan,tgonow..疑问句MustI,,•?Yes,youmust.（一定）No,youneedn,t./youdon'thaveto.（不必）Doyouhavetogotoday?Yes,wedo.否定句：Youdon'thavetoworryaboutthat.四、need与dare的用法对比表对比点needdare.情态动词+动词原形1）否定式2）疑问式Heneednot（needn*t）go.Needwedoitagain?—No,youneedn?tdoitagain.Hedarenotsayso.Dareshegooutaloneatnight?HowdareyousayI'munfair?Ifhedaredothat,he'11bepunished.（条件句）Idaresay.（固定用法）.行为动词+带to不定式1）肯定式2）否定式3）疑问式Heneedstogo.Hedoesn,t（doesnot）needtogo.Doesheneedtodoitagain?No,hedoesn,tneedotdoitagain.Hedarestosay.Hedoesnot（doesn,t）daretosay.Ifyoudaretojumpintothewaterfromhere,sodareI..didnotneedtodo表示过去没有必要做Shedidn'tneedtoattendthemeetingyesterday,andshestayedwithherchildren.（她没有参加）五、should与oughtto用法对比表对比点shouldoughtto1、表“应该”表劝告、建议Youshould1istentothedoctor*sadvice.WeshouldlearnfromZhangHua表示“有责任有必要”做某事Yououghttofinishyourworkbeforeyougohome.Weoughttohelpeachother.2、表“估计”Theyshouldgethomebynow.表示“非常可能”的事，可译为“总应该”Ifwestarttoworkrightnow,weoughttofinishitbeforelunch.（午饭前应当能干完）注：1）、should还可在虚拟语气中的使用2).注意:oughtto的疑问式及否定式Oughthetogo?Yes,Ithinkheoughtto.No,heoughtn,tto.否定式：oughtnottoa或oughtn'ttodo(不说oughttonotdo)反疑问句：oughtn't?六、shall与will的用法对比表shallWill.征询对方意见或请求指示，用于第一、三人称：Shal1I(we),,,?Shallhe(she),,,?WhereshallI(we)waitforyou?1.询问对方的意思或向对方提出要求:Willyou(please),,•?Won'tyou…？Wouldyouliketo…？(用would替代will更客气)Won'tyougoandseethefilm?你不去看电影吗?Yes,IthinkIwill.不,我想去。.表示说话人的“意愿”有“命令”“警告”“强制”“允诺”“决心”等,用于第二、三人称，要重读。YoushalldowhatItellyou(todo).我叫你干什么你就干什么。Everythingshallbedonetosavetheship.一定要竭尽全力来拯救这艘船。表示“意志”“意愿”，用于各种人称：Iwonftdoanythingyoudon'tlike.我不会做任何你不喜欢的事。Would表示过去时间的“意志”“意愿”Shylockwouldnottakethemoneyearlier.夏洛克先前是不肯要钱的。七:usedto与would用法对比表usedtowould.表示过去的动作、状态,重在与现在情况的对比,不一定要有时间状语。Iusedtoplaycardsalot,butnowIseldomplay.Myhometownisnotwhatitusedtobe.1.只表示过去动作的重复，有明确的时间状语IwouldgotoseemygrandfatheronSundaywhenhewasinthemiddleschool..would后只接表动作的动词，不接表认识或状态动词Heusedtobonervousintheexam.2.表示过去的习惯有时可互换:Whenwewereveryyoung,weusedto/wouldgoskatingeverywinter.2.表示过去的次数时，不能使用：(V)WewenttotheGreatWallfivetimeswhenwewereyoung.(X)Weusedtogo/wouldgototheGreatWal1fivetimeswhenwewereyoung.注:usedtodo的否定式:usedn'ttodo或didn'tusetodo(usedn*t也可写作usen't)疑问式：Didyouusetodo?Dicin'tyouusetodo?Usedyoutodo?Usedn'tyoutodo?情态动词表推测情态动词表推测的意义：1、大多数情态动词(除表'能力、许可、意志'外)，都可以表示推测,其程度有差异。按其可能性程度的高低排列为:Musi>will>would>oughtto>should>can>could>m