助动词与情态动词.ppt

常用在肯定句中，表示对过去发生行为的肯定推测，含有“一定”、“准是”的意思。ShemusthavestudiedEnglishbefore.Theroadiswet.Itmusthaverainedlastnight.(练习11172740)musthavedone表示对过去事情的否定推测，“不可能做过某事”。史密斯先生不可能去北京了，我刚才还在图书馆见过他。Mr.SmithcanthavegonetoBeijing,forIsawhiminthelibraryjustnow.玛丽不可能偷你的钱，她回家了。Marycanthavestolenyourmoney.Shehasgonehome.(练习282935)canthavedone/couldnthavedonemay/mighthavedone表示对过去发生行为的不太肯定的推测，含有“可能”、“也许是”的意思。Hemayhavefinishedhishomework.Hemightnothavesettledthequestion(练习25)He___youmorehelp,eventhoughhewasverybusy.mighthavegivenB)mightgivemayhavegivenD)maygive√1201Youcouldhavecompletedthetaskalittleearlier.02IcouldhavepassedtheexameasilybutImadetoomanystupidmistakes.表示本来能够完成的动作但没有完成。couldhavedoneshouldhavedone/oughttohavedone过去该做而实际上未做的动作或行为；否定形式shouldnothavedone/oughtnottohavedone发生了不应该发生的行为。Ishouldhavethoughtofthat.(练习2836)Theyshouldnothaveleftsosoon.Youshouldnothavetoldherthetruth.should/shouldnothavedoneneedn’thavedone表示过去做了某事，但没有做的必要，意为“本没必要…”。Youneedn’thavewokenmeup;Idon’thavetogotoworktoday.你本来没必要叫醒我Sheneedn’thavecomeheresoearly.她本来不必要来这么早。(练习2237)※didnotneedtodo动作并没发生YesterdayIdidn’tneedtogetupearly,soIgotupat9a.m.Thereisnolighton---they___beathome.A.can’tB.mustn’tC.needn’tD.shouldn’t2.MyMP4playerisn’tinmybag.Where___Ihaveputit?A.canB.mustC.shouldD.would3.Aleft-luggageofficeisaplacewherebags____beleftforashorttime,especiallyatarailwaystation.A.shouldB.canC.mustD.will4.I____havebeenmorethansixyearsoldwhentheaccidenthappened.shouldn’tB.couldn’tC.mustn’tD.needn’t5.–Shelooksveryhappy.She___havepassedtheexam.--Iguessso.It’snotdifficultafterall.shouldB.couldC.