1、虚拟语气（一）虚拟语气用于表示假设的条件状语从句，状语从句相当于汉语的“假如” “要是”等。If she invites me tomorrow, I shall go to the party.。If she invited me, I should go to the party. If she had invited me yesterday, I should have gone to the party.1、对 现在的 虚拟，表示与现在事实相反的假设时，条件状语从句的谓语动词用过去式（be 的过去式用were.而主句中的谓语动词用 would (should, could, migh
2、t) + 动词原形。见下表：条件状语从句的动词形式 主句的动词形式If+主语+动词过去式(be 的过去式 were) I (we)should+动词原形主语+would (might,could)十动词原形1、例句： If I were you, I should study English. If he had time, he would attend the meeting. If they didnt take physical exercises every day, they wouldnt be so healthy. If you went to bed earlier, yo
3、u would not be so sleepy in the morning. If this were the case, it would be very awkward.2、对过去的虚拟，表示与过去的事实相反的假设时，条件状语从句的谓语动词用过去完成时,主句的谓语动词用 would (should, could, might)+have+过去分词。见下表：条件状语从司的动词形式 主句的动词形式If+主语+had+过去分词 I (we)should+have+过去分词主语+would (might,could)+have 过去分词例句：If you had taken my advice
4、, you wouldnt have failed in the examination.I would have checked my paper again if I had had more time at yesterdays examination.He would have already recovered from his illness if he had seen the doctor in time. If we had known that she was to arrive yesterday, we could have met her at the station
5、. You didnt let me drive. If we had driven in turn, you wouldnt have got so tired. .3、表示与将来事实相反的假设，对将来表示怀疑，或将来的动作不太可能实现时，条件状语从句和主句的谓语动词有以下形式：（见表）条件状语从句的动词形式(三种) 主句的动词形式(1)if 十主语+动词过去式 (be 的过去式用 were)，通常要与一个表示将来的时间状语连用.(2)If+主语( 任何人称和数)+should+ 动词原形(3)if+主语 (任何人称和数)+were to+动词原形I(we)should+动词原形主语+wou
6、ld (might, could)+动词原形1）If it rains tomorrow, our picnic will be put off. 2）If it rained tomorrow, our picnic would be put off. 3）If it should rain tomorrow, our picnic would be put off. If I were to see her tomorrow, I would tell her the truth.If it were to rain tomorrow, the meeting would be put o
7、ff.。I bet Brazil will win the World Cup. If it should lose, I would treat you a meal.4、虚拟语气省略条件从句或主句表示虚拟语气的条件句的主句或从句有时可以省略，而省略部分的含义仍有所体现。1）省略条件从句，如：It would be very nice.You could have done it yourself. 2）省略主句：在强调条件从句时，常省略主句，这种句子常表示一种“已不能实现”的愿望，主要用于If only 引导的感叹句中。For example:If only he were here!If
8、 only I knew more!If only he had stayed with us!（二）虚拟语气的其他句型和用法1、用在“wish+宾语从句”中，表示很难实现或不能实现的愿望，可以翻译为“但愿”, “悔不该”等。表示现在不能实现的愿望，从句的谓语动词用过去式；表示将来的愿望，从句的谓语动词用“would (could)+动词原形” ；对过去的事情表示愿望，从句的谓语动词用 “had+过去分词” 或“could + have + 过去分词” 。注意：Wish 后面的宾语从句必须用虚拟语气，不管这个愿望是否能实现。如：I wish it were Spring all the yea
9、r round.I wish you could go with us.We wish we had arrived there two hours earlier.注意：wish 与 hope 接宾语从句的区别在于： hope 表示一般可以实现的希望，宾语从句用陈述语气。Wish 表示很难或不大可能实现的愿望，宾语从句用虚拟语气。We hope we will succeed.We wish we would succeed. 2、用在 as if/as though,或 even if/even though 引导的从句中: 如果从句中表示的动作发生在过去，则谓语动词用 had过去分词形式
10、；如果指的是现在的状况，则用过去式(be 用 were)；指将来则用 would(should, could)+动词原形。注意：究竟用什么时态，只看从句动作发生的时间，与主句的时态没有关系。He looked as if he were an artist.He speaks English so fluently as if he had studied English in the U.S.He always sounds as if he would help you.3、在 It is (high) time (that)句型中，后面的从句的谓语动词常用过去式 (be 的过去式用 we
11、re), 或者用should+动词原形(should 不能省略) 来表示。这句话的意思是“（现在）该” 。It is time we left/should leave.It is high time that you got married.4、在 I would rather (that)句型中，后面的从句的谓语动词用过去式(be 的过去式用 were)。这句话的意思是“我宁可” ，表示说话人的意愿。Id rather I were in the rain now.Id rather you did not tell him.5、用在 suppose 开头的祈使句中，从句的谓语动词变化与
12、as if 后面的动词变化规律相同，用过去式、过去完成式、或过去将来式。意思是“假如” ，但 suppose 是动词，不是连词。如：Suppose the boss walked in. What should I do?Suppose Saddam had not been captured. What would the U.S. do?6、用在 for fear that 或 lest 引导的从句中，表示 “怕” “万一”等意思。从句的谓语动词用 should动词原形，should 可以省略。如：She closed the windows for fear that she (shou
13、ld) catch cold.Lest the wall （should） collapse, they evacuated from the building.7. 在表示建议、要求、命令等意思的动词，如 arrange, command, demand, desire, insist, order, propose, request, require, suggest, beg, move（提议）后面的宾语从句中，谓语动词用 should + 动词原形，should 可以省略，而引导宾语从句的 that 不能省略。例如：We suggested that we (should) have
14、a meeting.We insisted that they (should) go with us.The doctor ordered that she (should) stay in bed for a few days.He demanded that we (should) start right away.The commander ordered that the bridge (should) be bombed.The villagers requested that the old building not be pulled down.8、使用上述表示建议、要求、命令
15、等意思的动词派生的名词，或在这些动词用作名词时，名词之后的从句用虚拟语气，即从句的谓语动词用 should动词原形，should 可以省略。从句的引导词 that 不能省略。这与上述第 7 项类似。如：He made a request that he (should) be allowed to take 3 days off. = He requested that he be allowed to take 3 days off.Our suggestion is that education (should) not be industrialized. = We suggest th
16、at education not be industrialized.The presidents decision is that the war against terrorism be launched at the right time. =The president decided that the war against terrorism be launched at the right time.9、上述动词在 It is suggested that, It is required that, Its requested that, Its ordered that, Its
17、 arranged that句型中，that 之后的从句用虚拟语气，即谓语动词用 should+动词原形, should 可以省略，但引导词 that 不能省略。如：It was suggested that he attend the conference.It was requested that the trial be openly reported.10、在 Its important (imperative, necessary, essential, vital, desirable, advisable, better) that句型中，that 引导的从句用虚拟语气，即谓语动词用 should 动词原形,should 可以省略。这个句型表示说话人的意见、要求等。For example:It is essential that there should be enough food and clothing for the winter.It is desirable that your wedding be postponed until next July.It is imperative that the board chairman be present at the board meeting.
