真实条件句和虚拟条件句的用法.doc

真实条件句和虚拟条件句的用法点击英语中的条件状语从句是表示前提或条件的从句结构，分为真实条件句和虚拟条件句（也叫非真实条件句）两大类。u 【真实条件句】1. 定义：真实条件句是表示将来的事件是可能发生的，或句中的条件是事实。2. 用法：真实条件句常见的有以下几种类型： If +现在时，主句+情态助动词。其中的现在时包括：一般现在时、现在进行时、现在完成时、现在完成进行式和can / must等,从句用一般将来时。例如：If it rains, the match will be cancelled. 如果下雨，比赛将被取消。(一般现在时)If I have read it, I will return the book on Monday. 如果我读完了，我会在周一把书还回去的。(现在完成时)If you are sitting in it, the police wont take your car away. 如果你坐在里面，警察是不会把你的小车弄走的。(现在进行时)If she has been waiting, she should / ought to phone me. 如果她一直等着，她应该打电话给我。(现在完成进行式)If she cant understand it, she can ask me. 如果她不明白，她可以问我。(情态动词can)祈使句+连词+陈述句。祈使句相当于if从句，比if 从句表示的更为紧迫。例如：Fail to pay and theyll cut off the electricity. 你 (如果) 不付款，他们就要断电。Tell us what to do and well get on with it. 你 (如) 告诉我们该做什么，我们就会干下去。Take a taxi, otherwise youll miss your train. 你 (如) 不叫出租车，你就会耽误火车。Drop that gun, or Ill shoot you. 放下枪，不然我就打死你。u 【虚拟条件句】1. 定义：虚拟条件句是表示从句中的假设条件与事实相反或是说话人认为不太可能实现的情况。2. 用法：与现在事实相反的假设、与过去事实相反的假设和与将来事实相反的假设。主句和从句中谓语动词的具体形式如下：用于与现在事实相反的假设（指现在的假设）。例如：This soup would taste better if it had more salt in it. 如果多放点盐的话，这个汤味道一定更好。I should be a bit more careful if I were you. 我要是你，会更加小心的。用于与过去事实相反的假设（指过去的假设）。例如：If I had not told him about it, he would never have known the fact. 要不是我告诉他那件事，他永远都不会知道真相。If you had previewed the text, you wouldnt have failed to answer the question. 如果你提前预习了课文的话，就会回答这个问题。用于与将来事实相反的假设（指将来的假设）。例如：If your mother knew this tomorrow, she would be angry. 万一你母亲明天知道了这件事，她会生气的。What would you do if you were to get into an accident? 如果发生事故，你怎么办？If you should change your mind, no one would blame you. 万一你要改变主意，没有人会指责你。英语中的条件句分为真实条件句和非真实条件句。一、真实条件句: 表示现实情况中可能实现的情况。真实条件句中的谓语动词一般用一般现在时代替一般将来时，用一般过去式代替过去将来时。例如：If it rains tomorrow, I will stay at home.They said they would let us know if they heard any news about him.二、非真实条件句: 非真实条件句也叫虚拟条件句，表示与现实情况相反的假设情况。主句和从句中的谓语动词都需要使用虚拟语气。在表示与事实相反的虚拟语气时，谓语动词有三种形式。其具体形式如下：时间概念 条件从句中的谓语动词 主句中的谓语动词与现在事实相反 did/were would(could/should/ might)+do与过去事实相反 had done/been would(could/should/might)+have done与将来事实相反 did/were would(could/should/ might)+ do should do were to do注意：1. 上述主句的谓语中，would表示结果，might表示可能性，could表示能力、允许或可能性，should主要用于第一人称后。2. 条件从句的谓语动词为be时，不管其主语是单数还是复数通常用were。例如：If he were here now, we could ask him about it. (与现在事实相反)3. 混合条件句。当条件状语从句表示的行为与主句表示的行为所发生的时间不一致时，动词的形式要根据它所表示的时间做出相应的调整。例如：If he had followed the doctors advice then, he would be quite all right now. （从句表示过去时间，主句表示现在时间）4. (省if )倒装的虚拟条件句。 虚拟条件句的从句部分如果含有were, should或had, 可将if省略，把were, should或had 移到从句主语前形成倒装。例如：Had I seen him then, I would have been very happy.5. If it werent for和If it hadnt been for是两个很常用的虚拟语气句型，其意为“若不是（有），要不是有”。前者谈论现在的情况，后者谈论过去的情况。【即学即练】一、用动词的适当形式填空。1. What will you do if it _ (rain) tomorrow? We have to carry it on, since weve got everything ready.2. She told me that she would not go with me if it _ (rain) the next day.3. If I _ (be) you, I would plant some trees round the house.4. If I had been you then, I _ (not quarrel) with him.5. If the United States had built more homes for poor people in 1955，the housing problems now in some parts of this country _ (not be) so serious.Key: 1. rains 2. rained 3. were 4. shouldnt have quarrelled5. wouldnt be二、选择填空1. John went to the hospital alone. If he _ me about it, I would have gone with him.A. should tell B. tellsC. told D. had told2. If we _ the other road, we might have arrived here in time for the meeting.A. take B. had takenC. took D. have taken3. If he _ my advice, he wouldnt have lost his job.A. followed B. should followC. had followed D. would follow4. Had I known about this computer program, a huge amount of time and energy _.A. would have been savedB. had been savedC. will be saved D. was saved5. _ for the free tickets, I would not have gone to the films so often.A. If it is not B. Were it notC. Had it not been D. If they were not6. T