虚拟语气

　　表示对不可能发生的事实的一种假设;或对已经发生过的事实进行一种相反情况的假设;

时     间	从句谓语形式	主句谓语形式
虚拟现在时 （与现在事实相反）	动词的过去式 （be一般用were)	should (would, could, might )+动词原形
虚拟过去时 （与过去事实相反）	had done	should (would, could, might )+have done
虚拟将来时 （与将来事实可能相反）	动词过去式 should+动词原形 were to+动词原形	should (would, could, might )+动词原形

　　一、虚拟式用于非真实条件句时的构成

　　If I had time, I would go to the movies with you.

　　If we hadn’t made adequate preparations, the conference, wouldn’t have been so successful.

　　If it were to rain tomorrow, the game would be put off.

　　[提示]

　　1. 在非真实条件句中, 有时从句的动词所表示的动作和主句的动词所表示的动作并不同时发生,这样的条件句中使用的虚拟式称为混合虚拟式。其构成视具体情况而定。

　　If I had taken my raincoat when I came out this morning, I would not be wet now.

　　If I were you, I wouldn’t have missed the film last night.

　　2. 当虚拟条件句的谓语动词含有were, should, had时，if可以省略，这时条件从句要用倒装语序，即将were, should, had等词置于句首，这种多用于书面语

　　If I were you, I wouldn’t feel sorry.

　　→Were I you, I wouldn’t feel sorry.

　　3. 有些句子从表层结构上看无if引导的非真实条件句, 但从深层意思上看是存在的。这种情况下主句动词仍需用虚拟式。这类句子中常出现without(如果没有), but for(要不是),otherwise(否则), but that(若不, 后接一从句)等词或词组。

　　But for your help, they couldn’t have succeeded.

　　要不是你的帮助, 他们就不会取得成功。

　　She wasn’t feeling well. Otherwise she wouldn’t have left the meeting so early.

　　她感不舒服。不然她不会那么早就离开会场的。

　　二、虚拟式也可用于其他情况

　　1. 在it’s necessary (important, natural, essential, proposed, required, suggested, impossible, strange) that…引导的主语从句中动词应用虚拟式,

　　表示必要、应该、建议、要求、惊讶、不相信等意。

　　It’s necessary that we (should) set out at once.

　　It’s proposed that a committee (should) be set up to look into the matter.

　　It’s only natural that you should be nervous. 你感到紧张是很自然的。

　　The dentist suggested that she (should) come another day.

　　It is highly important that we (should) combine revolutionary sweep with

　　practicalness. "对我们来说,把革命气概和实际精神结合起来是很重要的。"

　　It is impossible that he should have missed the train. 他不可能误车。

　　It’s strange that he should have failed in the exam.

　　2. 一想要(desire)二宁愿(prefer)三命令(order. command)四建议(advice. suggest. propose)五要求(demand. require. request. desire.insist)中，无论主句谓语动词为何种时态，从句的谓语动词都用：“should + 动词原形”或只用“动词原形”。

　　I suggest that we (should) go camping tomorrow.

　　He insisted that our laboratory reports (should) be handed in the day afterthe experiment was done. 他坚持要求我们在做完实验后第二天将实验报告交上来。

　　He asked that they (should) be allowed to use a dictionary.他要求准许他们用词典。

　　The director required that we should work all night主任要求我们通宵工作。

　　The mayor ordered that free food be distributed.市长命令发放食品。

　　The boss demanded that Mary (should) finish it within a week.老板要求玛丽在一周内完成它。

　　I propose we should have another meeting. 我提议我们再开一次会议。

　　I command that he go at once.我命令他立即就去

　　注意,以上句中insist意为“坚持要求”。如insist作“坚持认为”解, 则不需用虚拟式。

　　He insisted that he was right.

　　他坚持认为他是对的。

　　3. 虚拟式可用于wish后的宾语从句中, 表示与事实相反的愿望。

　　a、表示与现在事实相反的愿望，谓语动词用过去式

　　eg. I wish I had your brains.

　　我希望我有你那样的头脑。(事实：我根本比不上你)

　　b、表示与过去事实相反的愿望，谓语动词：had+done

　　eg. I wish I had known the truth of the matter.

　　我希望我原来知道这件事的真相。(事实：原来不知道)

　　c、表示将来难以实现的愿望

　　谓语动词：should/would + 动词原形

　　eg. I wish I should have a chance again.

　　我希望我还能有一次这样的机会。(事实：很难再有这样的机会了)

　　4. It’s (high, about) time that…的句型要求用虚拟式, 表示应该做还没做的事。((时节)正盛的;(时机)成熟的)

　　It’s high time that he stopped smoking.

　　It is high time you made up your mind.你该拿主意了。

　　It’s about time that we took our leave.

　　5. 在I would rather, had rather, would sooner后的宾语从句中, 动词也要求用虚拟式, 表示与客观事实不相符的一种愿望。

　　过去 had + 过去分词

　　现在 过去时(be 用were )

　　将来 过去时(be 用were )

　　I’d rather you left tomorrow instead of today.

　　I’d rather he hadn’t done anything like that.

　　6. 在as if (though) 引导的状语从句中, 谓语动词有时用虚拟式。

　　She looks as if she knew all about it.

　　They talked as though they had got acquainted with each other for years.