虚拟语气一．虚拟语气在虚拟条件句中的应用。
虚拟条件是相对于真实条件而言的。
如果假设的条件有可能发生或发生的可能性很大，就用真实条件句；反之，则用虚拟条件句。
如：If you don’t mind, I’ll turn on the radio. (I’m going to turn on the radio, if you ag ree.)真实条件句If I were you, I would do it some other way. (I’m not you, so I can’t do it some other w ay.)虚拟条件句。
1．虚拟从句与主句的谓语构成。
（1）. 一般时态下的虚拟语气句子的谓语构成；从句谓语：系动词be一律用were；行为动词一律用过去式主句谓语：would; could; might; should + 动词原形If I knew the truth, I would tell you.If I were you, I would receive his invitation.If there were no gravity, we should not be able to walk.（2）. 与过去事实相反的假设从句谓语：had +过去分词主句谓语：should; would; might; would + have +过去分词If I had known that you were coming, I would have met you at the airport.If I had more time, I would have finished my work.You could have done better if you had been more careful.（3）. 与未来事实相反的假设从句谓语：should; were to +动词原形主句谓语：should; would; might; could +动词原形If you should fail, what would you do?If you should encounter with any inconvenience, please don’t hesitate to let us know.If you were to try again, you might succeed.If the cover should have a crack in it, the harmful gas would come out and cause pollution. 注：1. 主句中第一人称用should，也可以用would，第二、第三人称只用would。
要表达“能够”情态意义时，主句中要用could；要表达“可能”情态意义时，主句要用might。
2. If引导的含有were, should, had 的从句， if若省略，从句中的were, should, had前置，构成部分倒装，但部分谓语提前的话，否定词不能提前。
Ex. Had it not been for the reservoir we’d never been able to beat the drought.Had she been given some hints, she could have answered the questions.2. 错综时间虚拟条件句主句与从句所指的时间不一致，例如从句是过去的假设，而主句是现在的结果，或者相反，等等，这时就要按照各自表示的时间来调整动词的形式。
如：1. If I had a bike, I would have lent it to you yesterday.2. If the weather had been more favorable, the crops would be growing still better.3. If he had followed the doctor’s advice, he would be quite all right now.3．含蓄虚拟条件句有时句中并未出现引导的条件句从句，其假设情况是用以下的几种情况来表示或暗示的。
（1）. 介词短语Ex. I could not have fulfilled the task without your help.But for air and water, nothing could live.In different circumstances, I would have said yes.He can use the bicycle on condition that he return it tomorrow.（2）. 某些连词( otherwise, but, supposing, provided, providing, unless, on condition that 等) Ex. She had intellect. Otherwise I would have scorned her. ( If she hadn’t intellec t…..)I would gladly lend you the money but I really don't have it. ( If I had money, …..)Supposing this ferry were to sink, what would we do?Provided the circumstances permit, I would climb the mountain.（3）. 通过上下文Ex. It would be a mistake to stand by. ( It would be a mistake if we stood by.)Such an accident could have been avoided. (if we had been more careful.)It was so quiet, you could have heard a pin drop (if you had listened carefully.) 二．虚拟语气在状语从句中的应用1. 在as if , as though引导的方式状语从句中。
在此类从句中，虚拟语气究竟采用何种形式，取决于从句中所明确表示或暗示出的时间，而与主句谓语动词的时态无关。
如果主从句谓语动词的动作同时发生，从句谓语动词就用过去式（be一律用were）；如果主句谓语动词的动作发生或正在发生时，从句谓语的动作正在进行，从句谓语动词就用过去进行式（be一律用were）；如果从句谓语动词的动作发生在主句谓语动词的动作之前，从句谓语动词就用过去完成式。
Ex. He talks / talked as if he knew everything.The wind is / was blowing so hard as though it were going to destroy the world.That tree looked as if it hadn’t been watered for a long time.2. 虚拟语气用于lest, for fear that 和in case引导的目的状语从句中在此类从句中，谓语多用动词原形或should加动词原形。
Ex. The driver looked over the engine carefully lest it should go wrong on the way.He handled the instrument with care for fear that it should be damaged.Ted doesn't dare to go out of the house in case he should be recognized.3. 虚拟语气用于so that和in order that引导的目的状语从句中。
在此类从句中，谓语多用may或mig ht ，can或could加动词原形，否定式则多用should not加动词原形。
Ex. Speak clearly, so that they may (can) understand you.I took my golf clubs so that I could play at the weekend.The teacher spoke slowly in order that all the students might ( could ) hear him clearly. He came in quietly in order that he shouldn't wake his wife.Let’s prepare a word list so that no one should have any difficulty in reading it.三．虚拟语气在宾语从句中的应用(1). “had hoped”这种句型表示一种“过去未实现的愿望”，从句谓语要用谓语“would +动词原形”Eg. I had hoped that Jane would become a doctor, but she wasn’t good enough at science.We had hoped that she would change her mind.We had hoped that State University would win the basketball game, but the other team play ed very well.(2). 虚拟语气用would后的宾语从句中。
Would (或‘d)是有实在意义的及物动词，是表示愿望（desire或wish）的一种特殊用法，其后常跟rather, sooner, (just) as soon含有“宁愿”“但愿”的意思，在句中作状语，用来修饰它。
would要求它的宾语从句用一般过去式，be一律用were.Ex. I would (that ) I were young again. I would (that)= (I wish )I would rather they came tomorrow.I could go myself, but I would sooner you went.I’d just as soon you didn’t take those important papers with you.注：* Would rather和 had rather都可以采用“’d rather”省略形式，后面通常使用省去that 的从句,从句中的谓语要用过去时。