发布时间 : 星期五 文章高考英语一轮复习 语法专题 第一部分 词法篇动词 专题3 情态动词和虚拟语气素材 外研版更新完毕开始阅读d6fc45dc48fe04a1b0717fd5360cba1aa8118cb0
专题3 情态动词和虚拟语气
◆情态动词的核心考点 1．can，be able to 和could
(1)can和be able to都表示能力，意思上没多大区别。但can只有现在和过去时，而be able to则有更多的形式。但当成功地完成某一具体动作时，通常不用could而用was/were able to来表示。这时was/were able to 相当于managed to，表示经过一番努力，终于能够完成某事。
Her mother can speak French.
The wounded man was still able to get to the village and was saved by the villagers in the end.
(2)表示猜测“可能”，一般用于疑问句和否定句。 —Can the news be true? —It can’t be true.
Someone is knocking at the door.Who could it be?
(3)can可以表示理论上的可能性，指常有的行为或情形，意为“有时会……”。 Anybody can make mistakes.
(4)表示请求、允许(表请求时，口语中常用could代替can使语气更委婉，回答时用can)。 Can I go now?
—Could I come to see you tomorrow?
—Yes，you can.(否定答语可用No，I’m afraid not.)
(5)表示惊异、怀疑、不相信的态度(主要用于否定句、疑问句或感叹句中)。 How can that be true？I can’t believe my eyes and ears. How could you be so careless? (6)can的特殊用法。
can but只有；can’t but不得不；can’t...too再怎样也不为过，越……越好 I can but wait. I can’t but wait.
You can’t be too patient to the customers. 2．may和might的用法
(1)表示允许、请求，might比may的语言更委婉一些。 —May I watch TV now?
—Yes，you may.(Yes，please.)
—No，you mustn’t.(No，you’d better not.)
(2)表示可能性时，might比may的可能性小，may表示的可能性比can小(主要用于陈述句、肯定或否定句，疑问句用can代替)。 The story may not be true. (3)表示祝愿(不用might) May you succeed!
(4)may/might as well最好还是……，不妨 You might as well do it now. (5)may/might well很可能 He may well be late for class. 3．must，have to和ought to的用法 (1)must
①表示“必须，应该，一定要”。强调主观看法，只有现在时形式，否定式是must not(mustn’t)。must开头的问句，其否定回答要用needn’t或don’t have to代替。 ②表示必然的结果。 All men must die.
③还可表示主语固执、偏要做他人不希望做的事。 It can’t help；he must do that.
(2)have to着重客观需要，能用于更多时态(过去时或将来时)。 He will have to be there before ten.
(3)ought to表示义务和责任，“应该”，比should语气要强。 You ought to take care of yourself. 4．need和dare的用法
(1)need表示“需要，必要”，只能用于否定句和疑问句。在肯定句中，常用must和have to代替。
(2)dare表示“敢”，通常用于否定句、疑问句和条件状语从句中。 Dare you go home alone at eleven in the evening? (3)need和dare的特殊用法
①need表“需要”时，可用want，require代替。
The desk needs to be repaired./The desk needs repairing.
②dare作实义动词时，在肯定句中要接to，在疑问句和否定句中to可省去。 He dares to catch a snake. I do not dare (to) complain.
Do you dare (to) swim in the river? 5．will和would的用法 (1)will
①表示请求、建议，常用于第二人称。 Will you please go with me? ②表示意愿、决定、允许。 I will never do that again.
③表示习惯性动作或某种倾向，“总是，惯于”，通常用于第三人称。 Rosa will always be late for school. (2)would
①表示请求、建议，比will委婉，指现在时间，多用于第二人称。 Would you like a cup of tea? ②表示过去习惯性动作或某种倾向。 We would play badminton on Sundays. 6．shall和should的用法 (1)shall
用于第一、三人称，在问句中表示征求对方意见或请求。 Shall I come in?
用于第二、三人称的陈述句中，表示命令或威胁。 You shall do as your father says. (2)should
①表示责任、义务，意为“应该”。 ②表示惊讶语气，意为“竟然”。 You should wear slippers in class.
③用于条件句，表示“假如，万一”，省去if，should可提至句首。 Should you be late，apologize to the teacher. 7．情态动词表示推测或判断的用法 下表即是表示推测的情态动词使用的场合： 情态动词 must may/might can/could 对现在和未 来的推测 must＋do may/might＋do can/could do 对过去 的推测 must have done may/might have done can/could have done 使用场合 肯定句 肯定句、否定句 否定句、疑问句(could可用于肯定句)
用来表示一种估计的情况should “按理会/估计会”should do 情态动词＋have done的用法 (1)should have done表示“本来应该做某事而实际上未做”，而shouldn’t have done则表示“本不应该做某事而实际上做了”。 You should have told me about it earlier.
You shouldn’t have said such words to your parents.
(2)ought to have done也表示“本应该……”，而ought not to have done则意为“本不应该……”。
You ought to have told me about it earlier.
You ought not to have said such words to your parents. (3)needn’t have done表示“本无必要做某事而实际上做了”。 You needn’t have walked so quickly since time was enough. (4)could have done表示“本来有可能……而事实上未做到”。 I could have come on time，but my car broke down on the way.
(5)may/might have done表示“过去可能发生过某事”或“本来应该或可以做某事(实际上没做)”。
You might have given him more help，but you were so busy. ◆虚拟语气的核心考点 1．虚拟语气用于条件状语从句
(1)表示与现在事实相反的假设，条件状语从句中的谓语动词用一般过去时(be动词用were)，而主句中的谓语动词用“would/should/could/might＋动词原形”。 If I were you，I would buy that house. If he had time，he should go with you.
(2)表示与过去的事实相反，条件状语从句中的谓语动词用过去完成时，主句中的谓语动词则用“would/should/might/could＋have＋过去分词”。
If he had taken my advice，he would have succeeded in passing the examination. (3)表示与将来事实相反，条件状语从句中的谓语动词用一般过去时或“should/were to＋动词原形”，而主句中的谓语动词则用“would/should/could/might＋动词原形”。 If it were to rain tomorrow，the football match would be put off.
(4)当条件状语从句表示的行为和主句表示的行为所发生的时间不一致时，动词的形式要根据它所表示的时间作相应调整。
If they had worked hard，they would be very tired now.(从句说的是过去，主句指的是
should have done 肯定句、否定句、疑问句