【情态动词的用法】
情态动词的用法
【情态动词的用法】
情态动词的用法
Grammar—Modal-verb
Ⅰ.情态动词
一、can/could
1.表示能力时
was/wereableto具体做成某件事(=managedtodo)
could只表示能够
2.can+感官动词
cantaste/see/hear/smell/feel/believe/decide/understand
3.can表示惊讶、不敢相信
Eg:Howcanyoudolikethis?
4.cannotbutdo
cannotchoosebutdo
cannothelpbutdo
Eg:Icannotbutfeelsorryforher.
Icannotchoosebutfollowheradvice.
5.cannot…over/enough/too…都不过分;越…越好
Eg:Youcannotoverpraisehim.
6.理论上的可能性:
Eg:Accidentscanhappenonsuchrainydays.
Anyonecanmakemistakes.
Thetemperaturecanfallto-40℃.
7.can’t表示否定推测:
Eg:Itcan’tbehim,forhehasgonetoParisyesterday.不能用mustn’t
8.can/could表示允许、请求
Can/MayIhelpyou?
IwonderifIcan/coulddosth.(此处could不表示时态)
-Can/Could/MayIuse…?
-Yes,youcan/may.
-No,youcan’t/maynot/mustn’t.(题目选项中如果表否定允许有mustn’t就选mustn’t)
You’dbetternot.(may问一般不用may回答)
I’dratheryoudidn’t.
9.can/could(not)havedone
(1)本能做、没能够
(2)过去可能会做、过去不可能做
Eg:HecouldhavekilledHarryPotter,buthedidn’t.(过去本能够)
Hecouldn’thavekilledhim17yearsago,andhecannotdoitnow,either.(过去没能够)
Canhehavegonetohisaunt’s?(过去可能会做)
Hecannothaveforgottenit.(过去不可能)
二、may/might
1.may/might推测性用法可能
Hemayberight.
Hemaynotcometoday(可能不)
Hemay/mightcometomorrow.
注意:只用于肯定和否定句中,不用于疑问句中
2.maynot可能不cannot不可能
HemaynotcomeHecan’tcome
3.mayaswell最好maywell理应,有足够的理由
Youmay(might)aswellstaywhereyouare.
-Shallwewalk?
-Wemayaswell.
4.表祝愿Mayyoubehappy!
5.may(might)+have+done表示对过去发生行为的推测,也许或许已经做
Itmayhavebeentrue.
Hemightnothavesettledthequestion.
Hemaynothavefinishedthework.
Ithinkhemayhavegonetobed.
6.may表示目的
Eg:Youmustgotobedearlysothatyoucan/maycatchthetrain.
7.表示让步
Eg:Howeverhardhemaytry,hecannotgetthefirstplace.
三、must
1.表示义务意为“必须”(主观意志)
Eg:Wemustdoeverythingstepbystep.
Youmustn’ttalktoherlikethat.
-Mustwehandinourexercise—booksnow?
-No,youneedn’t./No,youdon’thaveto.
2.肯定推测(绝对不能用于否定推测!否定推测用can’t/couldn’t)
Eg:Hemustbeill.Helookssopale.
She’swearingadiamondnecklace.Shemusthavealotofmoney.
3.偏要做,偏偏
Eg:WhymustrainonFriday?
Mustyouspeaksoloudly?
Ifyoumustsmoke,pleasegoout!
4.musthavedone想必准时一定做了某事,否定是can’t/couldn’thavedone
5.didn’tneedtohavedone过去没有必要做,具体是否做不强调
needn’thavedone本不必却做了
四、shall
1.在肯定句、否定句中表示命令、警告、威胁、许诺以及法律、规定、规章制度
Eg:Youshallleavetheroomatonce,andheshall,too.
Ithasbeenannouncedthatcandidatesshallremainintheirseatuntilallthepapershavebeencollected.
-whencanIgetmycomputerback?
-Well,youshallhaveitonSaturday.