2020湖南专升本英语备考：情态动词这样用才合适！

专升本英语考试对情态动词也有考察，情态动词如can,may,must,ought to,should,shall,would,need,dare,hadbetter，大家必须要掌握，下面小编就来说说怎么用这些情态动词，希望对大家有所帮助。
专升本备考：情态动词专项
情态动词表示说话人的各种态度，如允许、可能、能力、义务、意志、预测、必要等。要求掌握的情态动词主要有:
01 should/oughtto与shouldn’t
should“应该”
You should keep the room clean.
ought to“应该”
You ought to sleep early.
shouldn’t“不应该”
You shouldn’t speak loudly here.
02 can与can’t
can①表示能力，“能,会”②表示允许，“可以”
Sam can speak English well.
Can I borrow your bike?can’t
①“不会,不能”②“一定不，不可能”
I can't give you an answer now.
The man can't be my uncle.
03 may与might
may①表示请求、许可，“可以”②“有可能，也许”（把握性不大）
You may sit here if you want.Your sistermay be waiting for you now.
might①may的过去式。②表示请求、许可，语气比may更委婉。③表推测，“有可能，也许”，可能性低于may。
Might I smoke here?No one knows what mighthappen in the future.
04 must与mustn’t
①表示主观看法，“必须，一定”②肯定推测
You must finish your homework first!
They must be very tired after a long walk.
mustn’t禁止，一定不要
You mustn't play football on the road.
05 could与couldn’t
could①“能，会”表示过去的能力。②在疑问句中表示委婉的请求。③“有可能”
Jim could play the piano well when he wasyoung.
couldn’t“不能，不会”
He couldn't dive last year,but now he cando it.
06 need与needn’t
need“需要”
You need say sorry to him.
needn’t“不需要”
You needn’t go with me.
07 shall与had better
shall①表示询问、请求，用于第一、三人称。②表示决心、警告、命令，多用于第二人称。
Shall we go out for a walk?
You shall not bring your mobile phones tothe classroom in the exam.
had better“最好要”
You had better have breakfast,or you willnot focus on your work.
08 will与would
will表示询问、请求，用于疑问句中。
Will you pass me a book?
would表示自愿、主动做。
Jane said she would not talk with angryTom.
09 have to与don’t have to
have to“不得不”，多表示客观必要
I have to go to work every day.
don’t have to“没必要”
You don't have to come here so early.