1、情态动词动词分类实义动词：比如want、like、go等系动词：feel、taste、sound、look、smell（5个感官动词）等；助动词：do、does、did；will、shall；have、has等情态动词：can ，should，must，may等定义表能力I can play basketball表请求Can I leave now?表必要I must study hard.表建议You should finish your homework.情态动词的几大特点1情态动词+动词原形2情态动词否定后面直接+not3情态动词变疑问句，直接提前4情态动词无三单、无将来注意：have
2、to例外，用于第三人称单数时变成has to情态动词基本用法序号原形过去式普通含义推测含义1maymight可能，也许可能，也许2cancould能力；请求/3cantcouldnt不能，不可以不可能（100%确定）4willwould将要；一种意愿/5must/必须一定（100%确定）6mustnt/禁止/7need/需要/8neednt/不需要，不必/9should/应该/10shouldnt/不应该/情态动词表推测cant100%否定推测不可能She cant be Lucy.may不确定推测可能She may be Lucy.must100%确定推测一定She must be Lucy
3、.情态动词辨析1.表能力can能力I can play basketball.=I am able to play basketball.couldcan的过去式I could play basketball when I was young.=I was able to play basketball when I was young.be able to相当于can/could/2.表请求委婉程度：cancouldmay情态动词肯定回答否定回答canYes,you can.Of course.No,you cantNo,you mustnt(禁止)couldmayCan/Could/May
4、 I leave now?肯定回答Yes,you can/Of course.否定回答No,you cant/No,you mustnt3.表必要have to“不得不/必须”客观条件限制(被迫)dont have to “不必”=needntmust“必须”主观条件限制(主动)musnt “禁止”注意：must引导的疑问句情态动词肯定回答否定回答mustYes,you must.No,you neednt / No,you dont have toMust I finish my homework now?是的，你必须现在完成。Yes,you must.不，你不必现在完成。No,you ne
5、ednt / No,you dont have to4.表建议shouldshould“应该”shouldnt“不应该”常用于纠正别人,提出或征询建议had betterhad better do sth“最好（做某事）”had better not do sth“最好不（做某事）”易混淆辨析maybe副词，句首或者句末Maybe she is a teacher.may be情态动词+be,句中She may be a teacher.may情态动词，句中She may go to shop to buy something.情态动词中的need1). need 作情态动词用时, need do sth需要做某事I neednt go there too early.2). need作实义动词用时，有人称、时态和数的变化。need to do sth需要做某事I dont need to go there too early.3). need后面接doing表示被动：sth need doing =sth need to be done.The washing machine needs repairing. = The washing machine needs to be repaired. 洗衣机需要（被）修理。
