1、语法要点虚拟语气Subjunctive MoodI.什么是语气？语气是动词的一种形式，用以表示说话人对某种言行或某种事情的看法或态度。英语有三种语气：陈述语气，祈使语气和虚拟语气。陈述语气一般用来讲述事实或提出疑问。常常用于陈述句、疑问句和感叹句。e.g.I took a shower after supper.What are you going to do?What a beautiful flower!祈使语气主要用于祈使句。e.g.Get out of here!虚拟语气II.什么是虚拟语气？虚拟语气是一种特殊的动词形式，表示说话人所说的话不是事实，而是想象、假设、建议、打算、意见、愿
2、望、怀疑、推测、喜悦等等。e.g.If we had met her last night,we would have told her what had happened.如果我们昨晚见到她，我们就会告诉她发生了什么事。（实际上，我们并没有见到她，也没有告诉她所发生的事。）为什么要学习虚拟语气？虚拟语气是四级考试中重点考察的语法点。历年四级考试中，仅仅单项填空部分就一共出现了48道虚拟语气的题目！II.虚拟语气的最基本形式 非真实性条件句是虚拟语气最基本的表现形式。i.由“if”来引导的非真实条件句 组成方式：非真实的条件从句+假设结果（主句）最基本形式的表达方式种类种类 从句的动词形式从句
3、的动词形式 主句的动词形式主句的动词形式与现在事实相反与现在事实相反 动词过去式动词过去式 would/should/would/should/（bebe的过去式常用的过去式常用 might/could+might/could+were were有时第三人有时第三人 动词原形动词原形 称单数可用称单数可用was)was)与过去事实相反与过去事实相反had+had+过去分词过去分词 would/should/would/should/might/could+might/could+have+have+过去分词过去分词与将来事实相反与将来事实相反 1.1.动词过去式动词过去式 would/shou
4、ld/would/should/2.should+2.should+动词原形动词原形 might/could+might/could+3.were to+3.were to+动词原形动词原形 动词原形动词原形注意在主句中，should一般只与第一人称搭配，could和might各人称都可以使用，但would是最普遍，最常见的。Examples 如果他在这里，他就会帮助我们。If he were here,he would help us.如果昨天没下雨，我们就去踢足球了。If it had not rained yesterday,we would have played football.如
5、果敌人胆敢袭击我们，我们将把他们全消灭。If the enemy were to(should)attack us,we would wipe them out completely.ii.错综时间条件句有时虚拟条件从句表示的动作和主句发生的动作在时间上不一致。例如，一个与过去事实相反，另一个与现在事实相反。这种句子可称为错综时间条件句。这时，谓语动词的形式要根据各自表示的时间来调整。e.g.If he were alive now,he might have finished his scientific researches on the bridge building three yea
6、rs ago.如果他现在还活着，他可能三年前就完成了他的桥梁建筑科研工作了。More examples要是昨天不下雪的话，我们现在就应该在去上海的路上了。If it had not snowed yesterday,we would be on the way to Shanghai.要是昨天晚上医生来晚了的话，他今天就没命了。If the doctor had not come sooner last night,he would be dead today.iii.虚拟语气的倒装省略“if”的条件句考试重点最常见的形式：“if”引导的条件句但是，我们经常可以看到“if”被省略掉而把were
7、,had,should,could放在主语前面的条件句。这种句型与“if”引导的条件句在表达意思上无任何区别。只是这种句型主要用于书面语。倒装虚拟语气的用法如果条件从句中含有were,had,should或could,可以省略连词if,把这些词放在主语之前构成倒装句。e.g.假如我是你的话，我课后就多做练习。Were I(=If I were)you,I would do more exercises after class注意！如果条件从句是否定式，倒装时只能把not 放在主语之后，不能用缩写式把not 放在主语之前。e.g.Had you not told me about the mat
8、ter,I should never have known the whole thing.(不能说：Hadnt you told me)iiii.含蓄虚拟条件句在虚拟语气中，有的句子可能没有明显的由“if”引导的条件从句，但是，仔细一分析就会发现句子中隐含着一个条件，这种句子称为含蓄条件句含蓄的条件可以用下列方式来表达：（1）介词或介词短语 常见的有：but for（要不是）,with,without,in that position（在那个位置）,in the absence of（没有）,under,in,for the fear of e.g.But for your help,we
9、couldnt have succeeded in the experiment.=If it had not been for your help,如果没有你的帮助，我们的实验不会成功。没有空气就不会有风和雨Without air,there would be no wind or rain.=If there were no air,如果条件更好一些，我们会做得更好。Under a better condition,we would have done much better.(2)连接词常见的可以用来引导虚拟语气的连接词有:and,but,but that,or,or else,othe
10、r,otherwise(否则)等。e.g.Im really busy;otherwise,I would certainly go with you.=if I werent so busy 要不是由于交通事故，我就不会上课迟到了。（我本来上课不会迟到的，可是发生了交通事故）。I would not have been late for class but there was a terrible traffic accident.我本来可以写信给你的，可我没有时间。I would have written to you,but there was no time.=If there had
11、 been time,I would have written to you.III.虚拟语气的特殊形式虚拟语气的特殊形式是这一语法项目的难点。说它难是因为从逻辑思维和语言使用习惯上同汉语没有明显的联系。但是这种特殊形式在四级考试中出现的频率非常高。它的表达方式有如下几个方面：i.虚拟语气在 as if,as though,等引导的从句中的应用As if,as though可以用来引导状语从句或表语从句，表示猜测，假定，联想等等。虚拟语气在as if,as though引导的从句中的表现方式大致有三种：(a)动词的过去时(b)had+过去分词(C)would（或might)+动词原形e.g.H
12、e talks as if he knew all about it.他谈起来好象全知道似的。我记得整件事情，好象就发生在昨天似的。I remember the whole thing as if it happened yesterday.She cried as if her heart would break.as if,as though引导的从句中谓语动词可以用陈述语气，这特别是当表示的情况是真实的，或实现的可能性较大的时候。She looks as if she were sick.(实际上没有病）She looks as if she is sick.(实际上可能或的确是病了）i
13、i.虚拟语气在主语从句中的运用在“It is+某些形容词（或过去分词）+主语从句”的句型中，主语从句中的动词形式用“should+动词原形（should可以省略）”。常用的形容词有：necessary,important,essential,obligatory,vital,impossible,strange,urgent,desirable,natural,advisable,preferable等等常用的过去分词通常是表示提议、要求、命令等动词的过去分词。例如：decided,arranged,suggested,required,demanded,urged,proposed,reco
14、mmended,ordered,desired,advisede.g.It is advisable that a general announcement be made to the staff.最好给全体人员发个通知。需要给这台机器加润滑油了。It is required that the machine(should)be oiled.已决定推迟会议。It has been decided that the meeting(should)be put off.iii.虚拟语气在宾语从句中的应用在表示提议、要求、命令、意志等动词之后的宾语从句中，可以用“should+动词原形（shoul
15、d可以省略）”形式做谓语。这类动词有：advise,ask,beg,determine,require,suggest,request,demand,urge,propose,command,desire,insist,prefer,order,pray,recommend 等等e.g.She insisted that the seat(should)be booked in advance.她坚持要预定座位。他们要求他唱支歌。They requested that he(should)sing a song.我建议推迟会议。I suggest that the meeting(should
16、)be put off.iv.虚拟语气在表语从句、同位语从句中的应用在demand,motion,idea,proposal,suggestion,order,recommendation,requirement,decision,advice等表提议、要求、命令等名词之后的表语从句、同位语从句中，谓语动词可用“should+动词原形（should可以省略)”形式。e.g.He issued the order that the troops(should)withdraw at once.他命令部队马上撤退。我的建议是我们派几个同志去帮助别的小组。My suggestion is that
17、we(should)senda few comrades to help the other groups.他发出命令要求立即完成这项工作。He gave the order that the work be done at once.v.wish之后宾语从句中动词的三种形式动词wish后面的宾语从句，表示不可能实现的愿望，其动词形式有三种：与现在事实相反从句动词用过去时与过去事实相反 从句动词形式 “had+过去分词”与将来事实可能相反 从句动词用或不可能实现的愿望 “would或could+动词原形”形式我要是记得她的地址就好了。I wish I remembered her addres
18、s.我们真希望你来参加我们的新年联欢会。（但你没来）We wish you had come to our New Years party.“Ill be back before Christmas.”“I wish youd come back before Thanksgiving.”vi.虚拟语气在if only引导的从句中的应用 在if only引导的从句中，谓语动词要用虚拟语气，其用法与wish后宾语从句的用法基本相同，表示“但愿，要是就好了”之意。If only I knew what you wanted.要是我知道你需要什么就好了他要是准时到达就好了，那样就不会被处分了。If
19、only he had arrived in time,he would not have been punished.vii.虚拟语气在“its(high,about)time+that 从句”句型中的应用。在“its(high,about)time+that从句”句型中，从句的谓语动词经常用过去式，指现在或将来的情况。Its time you went to bed.你该上床睡觉了。是我们该走的时候了。Its high time that we were off.viii.虚拟语气在would rather等词后的用法在would rather,would prefer等词后面所跟的从句中
20、，也用虚拟语气，表示愿望，意为“宁愿，但愿”。“would rather+主语+谓语动词过去式”表示现在或将来的情况。“would rather+主语+过去完成时”表示过去的情况。我真希望现在是夏天，这样我就可以去游泳了。I would rather it were summer now,so I can go swimming.我真希望你昨天晚上没对她那么无礼。I would rather you hadnt been so rude to her last night.总结与现在情况相反的时候，谓语动词用过去时！与过去情况相反的时候，谓语动词用had+过去分词形式！主句中如果出现有表示命令，提议，要求，意志方面的词时，一定要警觉！99%的可能性就是要考虚拟语气！一般考的就是“should+动词原形”这一形式，四级的出题者往往在“动词原形”中考被动语态，在正确选项中往往把should省略掉，而成be done 的形式，要特别注意这一点！
