概念：虚拟语气表示说话人的主观愿望、猜 测、建议或事实不符的假设等，也可以表 示可能性较小的情况或不可能发生的情况 ，而不是客观存在的事实。虚拟语气是通 过句中谓语动词的特殊形式表现出来的。 虚拟语气在条件句中应用比较多。
类，一类为真实条件句， 一类为非真实条件句。非真实条件句表示 的是假设的或实现可能性不大的情况，故 采用虚拟语气。 ? If I have time tomorrow, I?ll go to see you. ? If I had time, I would go to see you.
? 1） 表达与现在事实相反的情况 ? 从句变化：if+ 主语+动词的过去式did或 were( be动词的过去式用were）
? 主句变化：主语+should/would /could/might+动词原形
Eg. If I were you, I would choose to work in a small town. Eg. If I knew her telephone number, I would tell you.
2） 表达与过去事实相反的情况 ? 从句变化：if+ 主语+动词的过去完成式即 had done
? 主句变化：主语+ should/would /could/might+现在完成时即have done
Eg. If they had worked hard, they would have passed the exam.
Eg. If he had taken my advice, he would not have made such a mistake.
? 从句有三种变化形式： if+主语+动词的过去式 if+主语+were to+动词原形 if+主语+should+动词原形
主句只有一种变化形式：主语+ would, should, could, might+ 动词原形do
Eg. If it snowed tomorrow, our plan would be postponed.
Eg. If you were to succeed, everything would be all right. Eg. If he should come here tomorrow, I would tell him the secret.
对将来情况的虚拟，也就是与将来的事 实相反，条件句中的谓语动词可以用should do, were to do, did三种表现形式表示， 但意 义略有不同。should表示的可能性最大、动 词过去式did的可能性次之，were to do的可 能性最小，所以大部分时候我们用were to do，表示基本无法实现。
4. 特殊虚拟条件句 ? 1）错综条件句 ? 有时，主句与从句的动作发生在不同的时 间，主句从句谓语动词的虚拟语气形式因 时间不同而不同，这种条件句叫作错综条 件句。分为时间错综和真假错综.
If you had followed my advice, you would be better now. If it had rained last night, it might be very cool today. If I had had more time, I would have been to the party, but I was busy the whole last week. If it were not for the fact that he can?t do this, I would ask him to come.
在虚拟条件句中，如果把连词if 省去，再把 were, should或had 移到从句的句首，实行 倒装，实现虚拟。
Should he agree to go there, we would send him there. Had you come earlier, you would have met him.
The football match would be put off if it____ A.will rain B. rains C. rained D. is rained The football match will be put off if it____
3）含蓄虚拟条件句 ※ 没有if，而隐含在某些词（without, but for, otherwise, or）中，实现条件假设。 But for your help, I would have failed. = If you hadn't helped me, I would have failed. 介词引导：with，without，but for/ that, except for等 ? 连词引导：or/otherwise等 Without electricity , the world would be dark .
5. 虚拟语气的一些特殊的用法 ? 1) 用于表示命令、建议、决定等词语之后 的that分句中。 ? demand, order, suggest, request, insist, advice, propose+ （should） do Eg. The doctor insisted that he not eat meat. Eg. His order that the troop not be send at once was carried out.
2) 常见的形容词有：essential, important, necessary, natural, imperative, strange ， vital, urgent, possible, appropriate 等。+（ should） do Eg. It is important that we （should）take care of the patient. Eg. It is strange that he behave like that.
常见的名词：decision, suggestion, demand, requirement, advice, order, instruction等 +（should） do
Eg. Our order is that you should return in 30 minutes. Eg. your advice that she wait till next week is reasonable.
She insisted that he steal the money. She insisted that he had stolen the money. ? Your pale face suggests that you（should） be ill. ? Your pale face suggests that you are ill. 如果suggest, insist不表示“建议” 或“坚 持要某人做某事时”，即它们用于其本意 “暗示、表明”、“坚持认为”时，宾语 从句用陈述语气
? 在for fear that, in case, lest引导的目的状语 从句中，若用虚拟语气，从句谓语should + 谓语动词原形（should一般不省）
He started out earlier lest he should be late. Bring an umbrella in case that it should rain later.
破题法则： 与现在相反的情况：用一般过去式表示； 与过去相反的情况：用过去完成时表示； 与将来相反的情况：用would/could/might+动 词原形表示 I wish you came to my wedding. ? I wish you would understand me completely .
It is （high/about） time （that）…中，从 句中的谓语动词多用动词过去式翻译为： 到了该做。。。的时候了 It is high time we went to school. It is about time you made up your mind.
破题法则： 表示与现在或将来相反的情况：常用一般过 去时； 表示与过去相反的情况：用过去完成时 I would rather you didn't smoke. He didn?t attend the meeting, I would rather he hadn?t been present.
7）由as if, as though引导的从句虚拟
? 破题法则： 表示与现在相反的情况：常用一般过去时； 表示与过去相反的情况：用过去完成时； 表示与将来相反的情况：用would/could+动 词原形。 If only she had lived a little longer. She behaves as if she were the manager of the company.
8. 关于if only 的虚拟语气 ? if only 引导的感叹句表示“但愿，要是。。 。就好了”，其用法和wish基本相同，只 是感情色彩更强烈。 与现在相反的情况：用一般过去式表示； 与过去相反的情况：用过去完成时表示； 与将来相反的情况：用would/could+动词 原形表示 If only he were here! If only I hadn't been busy yesterday! If only you would listen to our advice.
试比较 if only 与only if
If only 第一种含义与only if近似，意为“as long as”，“只 要”。 eg. If only it clears up, we?ll go. 第二种则是“expressing a wish or assumption”， “但愿；如果……就好了”。多用虚拟语气。 If only the alarm clock had rung. only if 表示“只有”； I wake up only if the alarm clock rings.
巧记 only 只有在前，但愿only 在后
9. 情态动词 虚拟结构
? Can/could have done 本能够或本有可能 （事实上未） ? Should have done 本应该做而未做 ? need have done 本需要做而未做 ? would have done 本会做而未做 Eg. You should have taken your mother?s advice. Eg. It?s so near, we needn't have taken a taxi.
Have a try
1. If I___ him yesterday, I ____him about it.
A. saw; asked B. saw; would have asked C. had seen; would have asked D. had seen; would asked
? It is hard for me to imagine what I would be doing today if I ____ in love, at the age of seven, with the Melinda Cox Library in my hometown. A. wouldn?t have fallen B. had not fallen C. should fall D. were to fall
? Yesterday, Jane walked away from the discussion. Otherwise, she ____ something she would regret later. A. had said B. said C. might say D. might have said
---Did Jack take the doctor?s advice that he ___in bed for a couple of days? --- If only he ___. A. lies; does B. lay; did
lay 放置，搁置laid laid laying
C. lie; did
lie 躺 lay, lain,lying 说谎 lied, lied, lying
D. lie; had
? All the doctors in the hospital insisted that he ____ badly wounded and that he ____ at once. A. should be; be operated on B. were; must be operated on C. was; should be operated D. was; be operated on
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