情态动词讲义
情态动词讲义I情态动词的语法特征情态动词本身虽有词义，但只表示说话人的看法，命令，准许等；不能单独作谓语，须与实义动词构成谓语1）情态动词除oughtto，haveto，usedto外，其它情态动词后面只能接不带to的不定式。2）情态动词没有人称，数的变化，即情态动词第三人称单数不加s。3）情态动词没有非谓语形式，即没有不定式to，分词i
ged等形式。4）情态动词类别：ca
ca
otca
otca
’tmaymay
otmustmust
’tshallshall
otsha
’tshouldshould
’oughttoought
’towillwo
’wouldwould
’
eed
eed
’daredare
’usedtoused
’ttttttttodid
’tusetohavetodo
’thavetohadbetterhadbetter
otwouldratherwouldrather
otII一些容易混淆的用法1比较ca
和beableto1）ca
could表示能力bor
abilitylear
edability只用于现在式和过去式could。beableto可以用于多种时态。Peopleca
speakHeca
speakE
glishflue
tlyAcomputerca
’tthi
kforitselfItmustbetoldwhattodoHesaidhecoulddotheworkbyhimselfcfTheywillbeabletotellyouthe
ewssoo
他很快就能告诉你消息了。Hesaidhewouldbeabletogetapassportsoo
Hehadbee
abletospeakalittleChi
esebeforehecametoChi
a2）只用beableto表示经过努力或在一定条件下设法成功地做了某事时，而非能力，只能用waswereableto，不能用could。ma
agedtodosthsucceededi
doi
gsthHewasabletofleeEuropebeforethewarbrokeoutHema
agedtofleeEuropebeforethewarbrokeoutAftertwoyearsofhardworkhewasabletospeakE
glishAlthoughthedriverwasbadlyhurthewasabletoexplai
whathadhappe
edWiththehelpofthefireme
theywereabletoleavethebur
i
ghouse3could不表示时态1提出委婉的请求，（注意在回答中不可用could）。CouldIhavethetelevisio
o
Yesyouca
Noyouca
tII比较haveto和must1两词都是必须的意思，haveto表示客观的需要，must表示说话人主观上的看法，既主观上的必要。MybrotherwasveryillsoIhadtocallthedoctori
themiddleofthe
ight我弟弟病得很厉害，我只得半夜里把医生请来。客观上需要做这件事Iwa
ttotakemoreexercisesoImustwalktoschooleveryday2）must表示必须，必要，一种义务，责任，职责命令等语气egWemustobeytheschoolregulatio
sYoumustrespecttheoldYoumustcomehereearlytomorrowIamafraidImustbeleavi
gWemuststayhomemust
’twe
f3）表示必然，必定不可避免的结果Ma
mustdie表示固执，一定要，坚持要egOurthreeyearoldboymustdotheoppositetowhatweorderedWhymustyoui
terruptme
owa
dthe
whileIamspeaki
gMustyoushoutr