发布时间 : 星期一 文章情态动词和虚拟语气2018年高考英语答题技巧及练习更新完毕开始阅读
二、 may，might
情态动词 用法 表示请求、允许 might不表示过去，仅表示语气更加委婉、客气 表示可能性 may/might 表示祝愿 固定用法 表示把握性不大的推测，不用于疑问句中；might表示的可能性比may更小 may可以用来表示祝愿，但句子要用部分倒装 may/might as well do sth.“不妨做某事；还是做某事为好” Might I make a suggestion? This coat may be Peter's.
He might be doing his homework now. May you succeed!
may表示请求许可时，其否定回答一般用mustn't。may not意为“可能不”，而can't意为“不可能”。
—May I use your computer? —Yes，you may.(No，you mustn't.) 三、will，would
情态动词 用法 用于第二人称作主语的疑问句表示请求 表示意志、决心或愿望 will/would 表示客观上的习惯，will表示现在，would表示过去 表示推测或猜想 表示按规律“注定会” Will you help me with the luggage? Would you pay me in cash，please? They asked if we would do that again. Oil will float on water.
would与used to
would表示过去的习惯时仅指动作，而且不与现在作对比；used to表示过去的习惯动作或状态，而且与现在作对比，说明现在这种动作或状态已经不存在。
In those days he would sit silently at the door for hours. He used to swim in the little river when he was a boy. 四、shall，should 情态动词 用法 用在第一、三人称作主语的疑问句中，表示征求对方的意见或请示 shall 用于第二、三人称作主语的陈述句中，表示说话者命令、警告、许诺等的语气 用在第三人称作主语的陈述句中，表示法律条文等的规定，意为“必须” 表示义务、责任、劝告或建议，意为“应该”，与ought to基本相同；should表示主观，ought to表示客观 should 表示预测，意为“应该会；按理说；想必会” 表示意外、惊讶、纳闷等感情色彩，意为“竟然；到底” Shall he come in or wait outside?
You shall remain in your seats until all papers have been collected. You should be careful when doing your job. We should arrive home before dark. How should I know it? 五、must，have to
must表示非常有把握的推测，仅用于肯定句。 You must be tired after the long journey.
表示“必须；一定”，must侧重主观，have to 侧重客观。 The children must be back by 4 o'clock.
表示说话者的感情色彩，暗含不耐烦或与自己的愿望相反，意为“偏要；
非要”。
If you must leave，please do it quietly.The baby is sleeping.
在回答must的问句时，否定回答通常用needn't或don't have to。 六、need，dare
need意为“需要”，dare意为“敢”，二者都既可作情态动词也可作实义动词，一般在疑问句和否定句中作情态动词用，在肯定句中作实义动词用。
—Need he go yesterday? —No，he needn't.
She dare not go out alone at night. 七、“情态动词＋have done”的用法 “情态动词＋have done”表示推测
可以这样用的情态动词有can，could，may，might，must，它们都表示对已经发生或完成的情况的推测。can仅用在否定句及疑问句中；must仅用在肯定句中；may/might不用于疑问句中。
There is nowhere to find them.Where can they have gone?
You can't have seen her in her office last Friday；she's been out of town for two weeks.
He is upset.He must have been punished.
Tom may have passed the driving test，but I am not sure about it. “情态动词＋have done”表示虚拟语气
可以这样用的情态动词有could，might，should，need(只用否定形式)等，它们都表示与事实相反的情况，一般意为“本??(事实却不这样)”。
Considering his ability，he could have done it better.
He might have given you more help，even though he was busy. You should have told me earlier.
I'm sorry.I shouldn't have been so rude to you. He needn't have gone to the station yesterday.
一、虚拟语气在非真实条件句中的用法 基本用法 情况 与现在事实相反 与过去事实相反 与将来事实相反 从句谓语动词 主句谓语动词 动词的过去式(be的过去式should/would/could/might用were) had done 动词的过去式、 should＋动词原形、 were to＋动词原形 ＋动词原形 should/would/could/might＋have done should/would/could/might＋动词原形 If I were you，I would do it in another way. If I saw her now，I would be very happy.
If he had taken my advice，he would have succeeded in the competition. If he should come here tomorrow，I should/would talk to him. If it were to rain tomorrow，the football match would be put off. 混合虚拟语气
有时非真实条件句的动作和主句的动作不同时发生，或主从句的动作有一个是事实，这种情况下谓语动词要根据各自的具体情况来确定。
If he had worked hard at his lesson，he would be in college now. 含蓄虚拟语气
有时非真实条件不是通过if引导的条件句来表现的，而是通过一些词或短语来表示，如without，but for，otherwise，but等。
I couldn't have finished the work on time without your help. But for your timely warning，we would have got into great trouble. 非真实条件句中省略if的用法
如果非真实条件句中有had，were，should，可省略if，而将had，were，should提前形成部分倒装。
Had he taken my advice，he would not have made such a mistake. Should it be sunny tomorrow，we would go hiking.