2016大学英语六级基础语法知识：情态动词思维导图

的、肯定性的推测，常译为“一定，准是，肯定”，其否定形式是can’t/couldn’thavedone，意为“决不可能，不太可能”。

e.g.Sincetheditchisfullofwater,itmusthaverainedlastnight.

却没有做，常含有后悔、责备、埋怨的口吻，意为“本应该”，“应该就好了”;e.g.Withalltheworkfinished,Ishouldhavegonetoyourbirthdaypartylastnight.

做的事却给做了，也常含有责备、不满之意，意为“本不该”。

e.g.Youshouldn’thavegonebacktoworkyesterdaywithoutthedoctor’spermission.

测，但不十分有把握，意为“可能，或许已经”。e.g.Atrafficaccidenthappenedyesterdayandadrivermayhavebeenhurt.

事，而实际未做、未能实现的事;有时也表示轻度批评，意为“本来可以，完全可以”。e.g.Thegasleakagecouldhavebeenavoidedifthe

gascompanytookimmediatemeasuresafterthewarningcall.

[例1]Youallthosecalculations!Wehaveacomputertodothatsortofthing.

A.needn’thavedoneB.mustnothavedone

C.shouldn’thavedoneD.can’thavedone

[例2]Itohimbecausehephonedmeshortlyafterwards.

A.oughttohavewrittenB.musthavewritten

C.couldn’thavewrittenD.needn’thavewritten

[例3]Youthoseletters.Whydidn’tyou

A.shouldpostB.musthaveposted

C.shouldhavepostedD.oughttopost

(责任编辑：田学江)