【The Subjunctive Mood】语气 (mood)是一种动词形式，用以表示说话者的意图或态度。英语中的语气有三种：陈述语气、祈使语气和虚拟语气。直陈语气(indicative mood),表示所说的话是事实。祈使语气 (imperative mood),表示所说的话是请求或命令。虚拟语气(subjunctive mood),表示说的话不是事实，或者是不可能发生的情况，而是一种愿望、建议或与事实相反的假设等。一. 虚拟语气在条件句中的应用学习虚拟语气在条件句中的用法之前我们必须清楚条件句的种类：条件句有真实条件句与非真实条件句(或称虚拟条件句)两种。真实条件句所表的假设是可能发生或实现的，句中的条件从句与结果主句都用陈述语气。如：If it doesnt rain tomorrow, I will go for a picnic. 假若明天不下雨，我就去野餐。Oil floats if you pour it on water. 你如把油倒在水里，油就浮起来。虚拟条件句所表的假设则是不可能或不大可能发生或实现的，句中的条件从句与结果主句皆须用虚拟语气。条件从句主句与现在事实相违背过去式（动词是be用were）should / would/could/might + 动词原形 与过去事实相违背had + 过去分词should / would/could/might + have +过去分词与未来事实相违背1) should + 动词原形2) were + 动词不定式3) 过去式（动词是Be用were）should / would/could/might + 动词原形1. 与现在事实相反的虚拟条件句，条件从句的谓语用动词的过去式 (be的过去式用were), 主句的谓语用should （would, could, might）+动词原形。If it were not raining, we should go for a picnic.如果现在不下雨的话，我们就出去野餐了。If he came here, he might be able to help you. 如果他来这，他就能够帮助你了。2. 与过去事实相反的虚拟条件句，条件从句的谓语用had+过去分词，主句的谓语用should （would, could, might）+ have 过去分词。She would have gone to the party if she had been invited. 要是当初她被邀请的话，她就会去参加这次聚会了。If she hadnt called me, I would have overslept this morning. 今天早上，她要是不叫我的话，我就会睡过头了。3. 与将来事实可能相反的虚拟条件句，条件从句的谓语用动词的过去式(be的过去式用were)； should动词原形；were to动词原形，主句用should （would, could, might）+动词原形。If I were to be twenty years old next year, I would take the course of French.明年我要是二十岁，我就会学法语。If it should fail, I would try again.要是失败了，我会再试一次。虚拟过去式有时并不表示“不大可能实现的假设”，而是表示一种希望或不希望发生的动作。如：If we caught the early train, wed get there by lunch time.假如我们赶上早班火车，到午饭时间我们就会到达那里了。(表希望)If we missed the train, we should have to wait an hour at the station.假如我们赶不上这班火车，我们就得在车站等一小时。（表不希望）4. 混合型的条件句当条件从句与主句所表的时间不一致时，虚拟语气的形式应作相应的调整。主句和从句的谓语动词并不相互呼应，这种条件句叫混合条件句。较多见的混合型条件句是从句用过去完成时（指过去行为），而主句用一般时（指目前状态）。 He would pass the test if he had taken my advice如果他听了我的劝告，他现在会通过考试。If I had spoken to him yesterday, I should know what to do now. 假如昨天我对他说了，现在我就知道该怎么办了。二. 连词if的省略如果虚拟条件句的谓语部分有were，had和should时，可省略if，把were，had和should放到从句主语前面去，多见于书面语。Had you not helped me, I should have failed.要是没有你的帮助，我就失败了。Were you in my position, you would do the same. 假如你处在我的地位，你也会这样干的。三. 含蓄条件句虚拟条件句中的条件从句有时不表出来，只暗含在上下文中，这种句子叫做含蓄条件句。含蓄条件句大体有三种情况。1) 条件暗含在短语中。如：But for your help we couldnt have succeeded in the experiment. 如果没有你的帮助，我们的实验是不会成功的。(暗含在分词短词but for your help)What would I have done without you? 如没有你，我会怎么办呢？(条件暗含在介词短语without you 中)2) 条件暗含在上下文中。We would have succeeded. 我们本来是会成功的。(可能暗含if we had kept trying)四. 不用if引导的条件从句虚拟条件句中的条件从句除用if引外，还可用when, unless, lest, suppose, as if, for fear, in case, on condition 等词语来引导。如：The peasants prepared to feed the city when it should be freed. 农民已准备在这座城市解放后供给粮食。Lest you should not have heard all, I shall begin at the beginning. 我怕你没有听全，所以我再从头开始讲一遍。Unless I were well, I wouldnt be at school. 除非我好了，否则我不会上学。Suppose you were given a chance to study in America , would you accept? 假如给你一个到美国学习的机会，你会接受吗？（suppose 或 supposing =what if）Supposing it were so？（=Supposing it were so，what would happen？）要是这样的话，会怎么样呢？He can use the bicycle on condition that he should return it tomorrow. 如果明天能还回来，他就可以借用这辆自行车。In case I forget , please remind me of my promise 如果我忘了，请提醒我的诺言。Susan is walking slowly ,as if she were tired. 苏珊走得很慢，就像是累了似的。与if一样，上述词语所引导的条件从句亦可用直陈语气，表可能实现或发生的事。虚拟语气讲解虚拟语气除主要用于条件句（也就是状语从句）外，还可用于主语从句、宾语从句、表语从句、定语从句等。1. 虚拟语气在主语从句中的应用“常用在It is (was)+形容词 / 过去分词+that引导的主语从句”的句型中的主语从句要用虚拟语气。主语从句的谓语用should+动词原形(或should+have+过去分词)或只用动词原形(尤其是美国英语)。should在此是助动词，本身并无实义，这种主语从句中的should有时有感情色彩。Its important that we（should）work out a plan. （带有“要求”的含义）Its better that he go at once. （带有“建议”的意思） 用于本句型的形容词并不多，常见形容词有：necessary，important，best, right, impossible，preferable，desirable, imperative, advisable，essential，reserved，urgent， 等。It is necessary that he（should）be sent there at once Its strange that he should say so.I was glad that he should go.It is important that we should speak politely. It is a pity that she should fare so badly.Its right that you should think that way. 用于本句型中的过去分词就是表示提议要求、命令等动词的过去分词，如suggested，settled, required，requested，demanded，urged，decided, proposed，ordered，desired，advised等。It is requested that Professor Liu（should）give us a lecture It is desired that we（should）get everything ready by tonightIm ashamed you should have done such a thing. It has been suggested that the meeting（should）be put off有人建议推迟会议。It is settled that you leave us, then?注意：这种句型中的主语从句也可用陈述语气，如：It was important that he made an explicit statement on this score last week. 他上个星期对于这一方面做了明确的说明，这是很重要的。2. 虚拟语气在宾语从句中的应用1). 宾语从句在表示提议、要求、命令、意志等动词后，其谓语用should+动词原形或只用动词原形的虚拟语气，作为suggest，request，demand，urge，propose，prefer，advise，insist，require，order