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1、GrammarModalverbs情态动词(I)Unit1Festivalsaroundtheworld·情态动词的语法特征1) 情态动词 不能单独做谓语,后面只能接不带to的不定式,除oughtto和have to外。2) 情态动词没有人称,数的变化,但有些情态动词,如can、will和have to有一般式和过去式的时态变化。I.can和could:可表示能力;许可;可能性;请求等1.Mostyoungpeoplecanusethecomputer.能力Othercelebrationswerehel
2、dwhenhunterscouldcatchanimals.2.--CouldIborrowyourdictionary?--Yes,youcan./No, youcan't.委婉的请求许可(注意在回答中只用can)ItisnowaChildren’sday,whentheycangototheirneighbor’shomesandaskforsweets.3.Theteachersaidthatwecouldnotleaveearly.Youmustn’ttakeitaway,butyoucanrea
3、dithere.许可4.Herbrothercan’tbeathomenow,becausehewasseenplayingbasketballinthestadiumjustnow.可能性(否定句和疑问句)Shecan/beabletosingthesonginEnglish.Thismachinecanmakeyoufeelcomfortable.另:1.can,beableto都可表示“能力”can的主语是人或物,beableto的主语是人2.can只用于现在式和过去式(could)。be able
4、 to可以用于各种时态。We’llbeabletofinishtheworksoon.3.表示成功地做了某事时,只能用was/were able to,不能用could。Thefirespreadthroughthehotelveryquickly,buteveryonewasabletogetout.II.may和might表请求,可能性---MayItakethenewspaperaway?---Yes,youmay./No,youmustn’t/can’t.1.may和might用于一般问句中表示委
5、婉的请求,常与第一人称连用,肯定回答用may、can,否定用mustn’t/can’t表禁止2.may和might表示“可能性”,(常用于肯定句或否定句)--AreyoucomingtoJeff’sparty?--I’mnotsure,Imightgototheconcertinstead.III.will和would表示意愿,请求,习惯2.Wouldyoupleasespeakagainmoreslowly?在疑问句中,will用于第二人称,表示请求或征求意见,would则语气更委婉1.—Writeto
6、mewhenyougethome.---Ok,Iwill.意愿,可用于各类人称3.Hewouldgoswimminginsummerwhenhewasinthecountryside.习惯,倾向Fishwilldieoutofwater.YoushalldoasIsay.Tellhimthatheshallhavethebooktomorrow.Nothingshallstopmedoingit.1.shall用于第二、三人称表示允诺、警告、命令、决心等。(命令)(允诺)(决心)IIII.shall,sh
7、ould和oughttoShallIopenthewindowforyou?Shallhefetchsomewaterforyou?2.在疑问句中,用于第一、三人称,Shall用来表示请求或征求意见。(征求意见)(请求)Youngpeopleshouldlearnhowtousecomputers.3.should常表示“应该”,与oughtto意义相近,Ihave10,000,andIthinkthatought(not)tobeenoughtous.Youshould/oughttohavetoldh
8、erthetruthearlier.4.should/oughttohavedone表示责备或批评,意为“本应该做到…但没有做到…”,5.should还有“竟然”之意。Ican’tbelievesuchakindmanshouldbesorudetoalady.IIIII.must和have to1.must在问句中,肯定回答用must,否定式用needn’t或don’thaveto,mustn’t表示“禁止,不允许”—Mus