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情态动词的用法高中阶段都学过哪些情态动词呢1can/could2may/might3must/haveto4shall/should5will/would6need/dare7oughtto情态动词的基本用法1can/could①Someofuscanusecomputersnow,butwecouldn'tlastyear.②----CanIgonow?----yes,youcan③Couldyoupleasesayitabitslowly?④Howcouldyoudosuchasillything?⑤Youcan’tbetoocarefulwhiledriving.（能力）（请求和允许）（请求）(惊讶)1.表示“能力”Someofuscanusecomputersnow,butwecouldn‘tlastyear.2.表示“请求，允许”----CanIgonow?----yes,youcan.Couldyoupleasesayitabitslowly?3.表示“惊讶”，通常用在否定句和疑问句中Howcouldyoudosuchasillything?4.can’t…too/enough表示“再…也不过分”；“越…越好”2may/might①MayIwatchTvaftersupper?Yesyoumay/No,youmustn‘t.②Mayyousucceed!Mayyouhaveaniceday!③Wemayaswellstaywhereweare.may/mightaswell还是……好（请求许可)（祝愿）2may/might1.表示“请求，许可”MayIwatchTvaftersupper?Yesyoumay/No,youmustn‘t.2.表示“祝愿”Mayyousucceed!Mayyouhaveaniceday!3.may/mightaswell+do“还是……好”Wemayaswellstaywhereweare.3must/haveto的用法①Youmustcometoschoolontime.Youmustn'twasteanymoretime②MustIcomebackbeforeten?Yes,youmust.No,youneedn't./don'thaveto④Ireallymustgonow.Ihavetogonow,becausemymotherisinhospital.（必须）（必须）③Ifyoumustgo,atleastwaituntilthestormisover.（非得，偏要）(必须)（禁止）(不得不）1.（用于否定句）表示“禁止”YoumustcometoschoolontimeYoumustn'twasteanymoretime2.（用于肯定句）表示“必须”MustIcomebackbeforeten?Yes,youmust.No,youneedn't./don'thaveto4.表示“不得不”Ireallymustgonow.Ihavetogonow,becausemymotherisinhospital.3.表示Ifyoumustgo,atleastwaituntilthestormisover.“非得，偏要”4shall与shouldshall1.用于一，三人称疑问句表示征求对方的意见和向对方请示Shallthedriverwait?Whatshallwedonext?2.用于第二、三人称陈述句中，表示命令、警告，允诺或威胁；以及法律条文规定YoushallgowithmeHeshallbepunishedYoushallhavethebookwhenIfinishitAllthechildrenshallgotoschoolattheageofseven.1.表示劝告和建议Youshouldstudyhard.2.表示竟然Youshouldbesorudetoyourmother.should5will与would的用法1.表示意志、意愿和决心Iwillneverdoitagain.Theysaidthattheywouldhelpus.2.表请求，建议Willyoupleasetakeamessageforme?Wouldyoupleasepasshimthebook?3.表功能Thismachinewon'twork.4.表示习惯性动作(与usedto有何区别)Fishwilldiewithoutwater.Everyevening,hewouldsitbythewindow.6need语dare的用法既可做实意动词又可做情态动词。做情态动词用于否定和疑问句而做实意动词可用于肯定，否定,疑问Howdareyousaysuchathing?Howdareyoutosaysuchathing?Hedaren’ttospeakEnglishbeforesuchacrowd,didhe?Hedaren’tspeakEnglishbeforesuchacrowd,darehe?情态动词表推测的用法二、情态动词表推测情态动词用法例句mustmust表示推测时只能用于肯定句中，意为“一定，必定”，表示十分肯定的语气(在疑问句中或否定句中要用can/could)。—It’stheoffice！Soyoumustknoweatingisnotallowedhere.—Oh，sorry.情态动词用法例句can(1)can用于肯定句中表示客观的可能性，意为“有时会”；(2)用于疑问句中可以表示推测，意为“可能”，有时表示一种惊讶的语气；(3)用于否定句中也可以表示推测，can’t意为“不可能”，语气很强烈。(1)ItisusuallywarminmyhometowninMarch，butitcanberathercoldsometimes.(2)Mr.Bushisontimeforeverything.Howcanitbethathewaslateforthemeeting？(3)(2013·高考安徽卷)Itcouldn’tbethevocabularythatcausedyoutheproblemintheexercisebecauseyouknowalotofwords.情态动词用法例句may/mightshould(1)may/might用于肯定句中可以用来表示不十分肯定的推测，意为“有可能”；(2)用于否定句中也可以表示推测，maynot意为“可能不”，表示一种不太确定的语气。(2013·高考北京卷)—Youneedn’ttakeanumbrella.Itisn’tgoingtorain.—Well，Idon’tknow.Itmightdo.should用来表示推测时意为“应该”，即含有“按道理来说应当如此”的意思。Thereshouldn’tbeanydifficultyaboutpassingtheroadtestsinceyouhavepracticedalotinthedrivingschool.情态动词+havedone三、情态动词＋havedone情态动词＋havedone用法例句musthavedonemay/mighthavedone表示对过去已经发生的行为进行推测,意为“一定做了某事”。Harryisfeelinguncomfortable.Hemusthavedrunktoomuchatthepartylastnight.表示对过去已发生行为的推测，意为“也许/或许已经(没有)……”。一般用于肯定句或否定句中。Sorry，I’mlate.Imighthaveturnedoffthealarmclockandgonebacktosleepagain.情态动词＋havedone用法例句can...havedone/cannothavedonecouldhavedone表示对过去发生的行为的怀疑和不肯定,通常用在否定句和疑问句中。(can换成could时语气较委婉)①Ican’tfindhimanywhere.Wherecanhehavegone？②Theboycan’thavefinishedreadingthebooksosoonbecauseitisdifficulteventoanadult.本来能够而没有做(2014·高考福建卷)Hecouldhavegoneonregrettingit,astoomanyofusdo.情态动词＋havedone用法例句mighthavedoneshould/oughttohavedone表示本来可能……，但实际上没有发生的事情。Youshouldnotswiminthatsea.Youmighthavebeeneatenbyashark.(1)用于肯定句时，表示本该做某事而实际上未做；(2)用于否定句时，则表示不该做的事反而做了。①Youshouldn’thavedoneitsocarelessly.②Yououghttohavereturnedthebookearlier.③Yououghtnottohaverefusedhisoffer.情态动词＋havedone用法例句needn’thavedone表示做了本来不必去做的事，“没必要做而做了”。注意didn’tneedtodo表示“没必要做而实际上也没有做某事”。①Youneedn’thavebroughtthebookbecauseTomhasonehere.②Ididn’tneedtobuythedictionary.Ihadacopyathome.