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：
① 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 won’t 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 can’t understand it, she can ask me. 如果她不明白，她可以问我。(情态动词can)
②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 they’ll cut off the electricity. 你 (如果) 不付款，他们就要断电。
Tell us what to do and we’ll 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 you’ll miss your train. 你 (如) 不叫出租车，你就会耽误火车。
Drop that gun, or I’ll 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：
①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。
②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 wouldn’t 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。
③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。
【即学即练】
I. 用括号内所给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 we’ve got everything ready.
2. If I had been you then, I him. ( not quarrel) with
3. If I (see) him tomorrow, I would be very happy.
4. If I asked him, I’m sure he (help) me.
5. If I’d left sooner, I (be) on time.
Ⅱ. 单项填空：真实条件句和虚拟条件句的用法比较。
1. ① If he in a day or two, I would wait for him.
A. returns
B. should have returned
C. were to return
D. have returned
② If he in a day or two, I will wait for him.
A. returns
B. should have returned
C. were to return
D. have returned
2. ① If I time, I a chat with you soon.
A. have; will have
B. had; will have
C. had had; would have had
D. have had; would have had
② If I time last night, I a chat with you.
A. have; will have
B. had; will have
C. had had; would have had
D. have had; would have had
3. ① If it this afternoon, we’ll put off the sports meet.
A. rain
B. rains
C. rained
D. will rain
② If it even a drop this spring, we would have had a better harvest.
A. rained
B. rains
C. had rained
D. have rained
虚拟语气中的含蓄条件句常见用法 先看一道高考题： ____ more attention，the trees could have grown better． A．Given B．To give C．Giving D．Having given （答案是A） 句中"．．．the trees could have grown better"是一个表达虚拟语气的句子。题中要求选择的是如何表达假设条件的形式。如果我们把这个句子用另一种形式"If they had been given more attentio n ，the trees could have grown better．"来表示，就不难理解了。很多情况下，在表示假设的虚拟语气中，有时假设的条件并不以条件从句的形式表达，而是通过上下文或句中内在的逻辑关系，或用其它形式表达出来，我们称之为"含蓄条件句"。 含蓄条件句主要通过名词、连接词、不定式、分词、动名词短语、介词短语及分句来暗示。这些表达形式在句中实际起着虚拟条件从句的作用。现分述如下： 一、介词短语 常用来表示虚拟条件的介词有with，without，in，under，but for等等，它们表示的虚拟条件都可以被if从句替换。 （1）without，with without表示否定的条件，意为if．．．not；with与without意义相反，表示肯定的条件。如：Without air，there would be no living things．（without air ＝if there were no air）没有空气，便没有生物。 With her help（＝If I had her help），I would do the experiment well．假如有她帮助，我就可以把这个实验做好。 （2）under Under the leadership of a less experienced person，the experiment would have failed．（u nder．．．＝If there had been the leadership of a less experienced person）假设在一个缺少经验的人领导下进行实验，实验准会失败。 （3）in I would have lost my head in that position．（in that position ＝if I had been in that po sition）我处在那种情况下，是会丧失理智的。 （4）but for
虚拟语气详解 虚拟语气表示说话人的主观愿望（往往与客观事实相反），或是表示假象和猜测。虚拟语气无论从形式上还是时态上都比较复杂，需要归类记忆。 虚拟语气大体分为三类：(1) be型虚拟(2) were型虚拟(3) if 条件句及主句虚拟下面会详细说每种虚拟形式的特征和规律，考试时先判断属于哪种虚拟类型，剩下的皆是套路~ （1）be型虚拟（基本是套路） 形式：should + 动词原形，should可以省略 用法：1）表示“命令、建议、要求”等意义词语之后的宾语从句用be型虚拟，常见的词如下: demand, desire, insist, order, ask, command, propose, recommend, suggest, prefer, require, request等 最常见的形式是这类动词后面接着一个宾语从句，则宾语从句的谓语部分要用（should）+ 动词原形来虚拟 例: We demand that the meeting（should）be postponed. The manager suggested that we (should) work together. 注意：有时候你所见到不一定是上述动词引导的宾语从句，而是由上述词变体后所引导主语从句(it做形式主语，如：it is advised/ suggested/ requested/ ordered/ proposed that…)、表语从句或同位语从句 例如：It is required that the students (should) learn a foreign language. (主语从句) The requirement is that all the equipment in the meeting room (should) be checked twice before. (表语从句) We didn’t stand for his proposal that the meeting (should)be postponed. (同位语从句) 只要看到句中有上述动词或其变体，不管词性怎么变、句型怎么变，都用be型虚拟！ 特例：suggest和insist这两个比较特殊，当suggest作“暗示、表明、说明”讲，insist 作“坚持说”讲，后面一般跟的是客观事实，不需要虚拟~这是一个比较重要的考点，体会下面两组句子： We all suggest that a lab (should) be built. 我们都建议建一个实验室。 Her expression suggests that she is angry. 她的表情说明她生气了。 She insisted that we should find the source of the river. 她坚持主张我们应该找到河的源头。 She insisted that she had done nothing wrong. 她坚持说自己没做错事。 suggest 的区别很明显，但insist有点难辨别，一般来说如果insist后面跟的是某种主张，或是坚持要做一件事，那么用虚拟。 2）表示主观看法，常表示“某事是必要的、重要的。。。怎么怎么样的”，尤其是在“ it is +名词/形容词+ that从句”结构中，常见的形容词包括：advisable, desirable, essential, imperative, important, necessary, obligatory, proper, dispensable, impossible, natural, surprising等 例如：It is advisable that you (should) leave now. It is necessary that teenagers (should) take part in outside activities. It is of great importance that smoking (should) be banned in public area.
虚拟语气(一) 一、考点聚焦 1、虚拟语气用于条件状语从句中 If I were a boy, I would join the army. If she had time, she should go with you. If h e had taken my advice, he would have succeeded in the competition. If i t were to rain tomorrow, the football match would be put off. If I had time, I would attend the meeting. If he had hurried ,he could have caught the train. If I were to go abroad ,I would go to America 如果我是你，我就会努力学习 If I were you, I would work harder at my lessons. 如果我知道他的电话号码，我就给他打电话了 If I had known his telephone number, I would have called him. 如果明天下雨的话，我们会取消比赛． If it should \were to rain, we would call off the match.
使用虚拟条件句要注意的几点： １．当条件状语从句表示的行为和主句表示的行为所发生的时间不一致时，被称为：错综时间条件句“，动词的形式要根据它所表示的时间作出相应的调整． If you had followed my advice , you would be better now. 如果你听我的建议，你现在就会痊愈了． If you had studied hard before, you would be a college student now. 如果你努力学习的话，你现在就会是大学生了． If they had worked hard, they would be very tired now.(从句说的是过去，主句指的是现在) ２．省略句 在条件句中，可省略if，把were ,had, should 提到句首，变为倒装句式．If I were at school again, I would study harder. Were I at school again, I would study harder. If you had come earlier, you would have met him. Had you come earlier, you would have met him. If it should rain tomorrow, we would not go climbing. Should it rain tomorrow, we would not go climbing. Were I a boy, I would join the army. Had he taken my advice, he would have succeeded. Were it not for the expense, I would go to Britain. 2、虚拟语气用于名词性从句 （1）虚拟语气在宾语从句中的运用。 ①“wish + 宾语从句”表示不能实现的愿望，译为“要是……就好了”等。 表现在过去时 表过去过去完成时 表将来would, might, could＋动词原形 I wish it were spring all the year round. I wish I had known the answer. I wish I could fly like a bird. I wish (that) I were a bird. I wish (that) I had seen the film last night. I wish (that) I would\could go.
If条件句和虚拟语气 if 条件句和虚拟语气 包含条件从句的句子叫条件句。条件句有两类：一类是真实条件句（First conditional）,一类是非真实条件句(Second Conditional)。如果假设的情况是有可能发生的，就是真实条件句；如果是纯属假设情况或是不可能发生或可能性不大的情况，则是非真实条件句。 1.真实条件句,可用if和unless引导 1）一个动作发生，另一动作随之发生 I’ll lend Peter the money if he needs it. If he has time, he will come. If he doesn’t come before 12 o’clock, we won’t wait for him. I shall go tomorrow unless it rains. I won’t go to her party unless I am invited. 2）表示命令、建议或请求,这时的if等于when If she telephones, let me know. Give my love to Lawrence if you see him. 3)will用于if从句中，不表示将来，而表示愿意或坚持的意思 If you will come this way, I’ll take you to the manager’s office. If you will get drunk every night, it’s not surprising you feel ill. 2. 非真实条件句
非真实条件句包括虚拟条件句和错综时间条件句 1）虚拟条件句分三类，其结构列表如下： If I become president, I’ll make all of my people live a happy life. (竞选总统的候选人这样说) If I became president, I’d make all of my people live a happy life. (一个小学生这样说) l 以下与现在事实相反 He wouldn’t feel so cold if he were indoors. I am sorry I am very busy just now. If I hade time, I would certainly go to the movie with you. l 以下与过去事实相反 If you had come here a little earlier, you would have met the pop star. I don’t know what would have happened if Jane hadn’t been able to speak Japanese. l 以下推测将来 If I were to do the work, I should do it in a different way. If it should rain again, what else could we do? 2) 错综时间条件句
if条件状语从句中的虚拟语气 一、if条件状语从句中虚拟语气的判断判断是真实条件句还是非真实条件句。 只有在非真实条件句中才使用虚拟语气。通过句子意思，看假设的条件是否能够实现， 能够实现是真实条件句，不能使用虚拟语气； 假设的条件不能实现则是非真实条件句，要用虚拟语气。 1. “后退一步法”后退一步法是指在准确地判断了该句与哪一事实相反后，按虚拟语气的后退一步法处理从句谓语动词的时态。即：在非真实条件状语从句中，谓语动词按正常情况“后退一步”。也就是： ①与过去事实相反，在从句中用过去完成时形式表示。 ②与现在事实相反，在从句中用过去一般时形式表示。 ③与将来事实可能相反，在从句中用过去将来时形式表示。主句中则用情态动词would, should, could 等加一个与从句一致的动词形式。 例：⑴、If I had come her yesterday, I would have seen him. ⑵、If I were a teacher, I would be strict with my students. ⑶、If it should snow tomorrow, they couldn't go out. 2、注意事项： ①if条件句中如有were, should, had，可以省去if，并使用倒装语序。 ②在现代英语中if条件状与从句中的谓语动词如果是be其过去形式一般用were。 二、虚拟语气在if 引导的条件句中的用法： 1. If it weren’t for your help, we would get into trouble. 如果没有你们的帮助，我们就会陷入困境。（而事实上得到了你们的帮助） 2.If the weather were fine, I would go there. 如果天气好，我去那儿。（事实天气不好） 3.If I were you, I would read it again. 如果我是你的话，我再读一遍。（事实上我不是你） 4.If time permitted, I would write it again. 如果时间允许的话，我再写一遍。（事实上时间不允许） 5.If it weren’t snowing, we wouldn’t stay in the house. 要是现在不下雪的话，我们就不会待在屋里。（事实上现在下雪） 6.What would I do if I were in your place?要是我处于你地位我会怎么办？（事实上我不在你的位置上） 7.If he hurried, he could catch the first bus. 他要是快点能够赶上头班公共汽车。（可是他不着急） 8. If I were you, I should buy it. (从句用过去式动词were，主句用动词原形buy) 9. If I had time, I would study French. (如果有时间，我会学习法文。)（从句用过去式动词had，主句用动词原形study） 10. If she knew English, she would not ask me for help. (如果她懂英文，她就不必要我帮了。)(从句用过去式动词knew, 主句用动词原形ask) 注意：如果动作在进行中，主句要用："主语+ would be + 进行式动词+ ……" 14. If they were here, he would be speaking to them now. (从句用过去式动词were, 主句用would be speaking)
Subjunctive Mood Ⅰ. Listen to the songs and fill in the blanks Number one: If _______________, _____________so high That the only people near me Would be the pilots in the sky. And If _______________, _______ so gracefully Through the air so all mankind could see. If _______________ Number two: If ______________I'd never hear your voice again, ___________each thing you ever said And on those lonely nights I could think of them once more And keep your words alive inside my head If _______________I'd never hear your voice again Number three: If I ______________, I _______________ in your way So I'll go, but I know I'll think of you every step of the way And I will always love you I will always love you Number four: yeah if ___________, then money, fame and fortune never _____________ If ____________, _____________a party( it'd be ecstasy(狂喜)) yeah if __________ you y-y-y-y do y-y-y-y-y do y-y-y-y-y do If _____________ that would be the only thing I'd ever need Subjunctive mood is used to talk about situations that are ______ true or _____ likely to become true. Ⅱ Observe the following sentences and put them into throw groups 1.If it were Sunday tomorrow, I would go and see my friends. 2. If she hadn't called me, I could have overslept(睡过头) this morning. 3. If he were you, I might go and try. 4. If I had time right now, I should certainly help you. 5. If I had known your telephone number yesterday, I would have telephoned you. 6. If it should rain in the near future, the crops could be saved. 7. If he were here tomorrow, I should speak to him. 8. If we had no air and water, we wouldn't survive. 9. If it snowed tomorrow, I might stay at home. 10. If you were to be a millionaire soon, what would you do with your money? Contrary to the present:__________________ Contrary to the past:_____________________ Contrary to the future:___________________ Ⅲ Structures of subjunctive mood 1. 虚拟条件从句主句 与现在事实 相反的假设If+S+________________ S+_____________________ 与过去事实 相反的假设If+S+ ________________ S+_____________________ 与将来事实 相反的假设 _______________ If+ S+ _______________ _______________ S+_____________________ 2. If 的省略:________________________________________________ 3. 错综条件句:______________________________________________ 1)If you had followed my advice the other day, you would feel better now.
if引导的条件句中的虚拟语气 虚拟语气表示一种不能实现的假设。该语法主要用于if条件状语从句。 一、if引导的条件状语从句的分类及虚拟条件句的判断 1、可以把条件句分为两类： 1).真实条件句（Sentences of Real Condition）：凡是假设的情况发生性可能很大，就是真实条件句。例如： ⑴、If I have time , I will help you with this work.如果我有时间会帮助你做此工作的。 (2)、If time permits, we'll go fishing together.(如果有时间的话，我们就一起去钓鱼。） 2).虚拟条件句（Sentences of Unreal Condition）：当假设是不大可能实现时，就是虚拟条件句。例如： ⑴、If I were you , I would have attended the meeting. 如果我是你的话，就去参加会议了。 ⑵、If he had come here yesterday, he would have seen his ol d friend.假如他昨天来这儿的话，就会看见他的老朋友。 ⑴、If it had rained yesterday, we would have stayed at home.（如果昨天下雨的话，我们就会留在家里。） 2、.if条件状语从句中虚拟语气的判断 判断是真实条件句还是非真实条件句。只有在非真实条件句中才使用虚拟语气。通过句子意思，看假设的条件是否能够实现，能
够实现是真实条件句，不能使用虚拟语气；假设的条件不能实现则是非真实条件句，要用虚拟语气。 判断这个假设是与哪个事实相反。通常有三种情况：①与过去事实相反。②与现在事实相反。③与将来事实可能相反。 3、“后退一步法” 后退一步法是指在准确地判断了该句与哪一事实相反后，按虚拟语气的后退一步法处理从句谓语动词的时态。即：在非真实条件状语从句中，谓语动词按正常情况“后退一步”。也就是： ①与过去事实相反，在从句中用过去完成时形式表示。 ②与现在事实相反，在从句中用过去一般时形式表示。 ③与将来事实可能相反，在从句中用过去将来时形式表示。 主句中则用情态动词would, should, could 等加一个与从句一致的动词形式。例： ⑴、If I had come her yesterday, I would have seen him. ⑵、If I were a teacher, I would be strict with my students. ⑶、If it should snow tomorrow, they couldn't go out. 4、注意事项 ①if条件句中如有were, should, had，可以省去if，并使用倒装语序。 ②在现代英语中if条件状与从句中的谓语动词如果是be其过去形式一般用were。
虚拟语气讲解 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 doesn’t 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。 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, might，could）+动词原形。 如：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。 （事实是：天在下雨，我们不能出去野餐。表示愿望。） If he came here, he might be able to help you. 如果他来这，他就能够帮助你了。 （事实是：他没来这，他不可能帮助你。表示对他的良好印象。）
高考虚拟语气试题 1. ____ to the doctor right away, he might have been alive. A. If he went B. Were he gone C. Should he have gone D. Had he gone 2. If you were older, I ____ you to go there yesterday. A. will allow B. should allow C. would have allowed D. had allowed 3. If we ____ here ten minutes earlier, we ___ the bus. A. arrived/would catch B. arrived/would have caught C. had arrived/had caught D. had arrived/would have caught 4. If I ___ more time, I would have gone with him. A. had B. had had C. have had D. would have 5. If he had not gone out in the storm _____. A. he will be alive now B. he would be alive now C. he would have been alive now 6. If it ___ tomorrow, what would we do? A. rains B. were to rain C. would rain D. rain 7. If only I _____ how to operate an electronic computer as you do. A. had known B. would know C. should k now D. knew 8. If it ___ rain, we ___ get wet. A. is to, should B. were to, would C. were going to, would D. was going to, should 9. If he ___ to the teacher attentively, he ___ the answer to the problem now. A. had lis tened, would have known B. listened, would know C. listened, would have known D. had listened, would know 10. ---- I thought you would come back tomorrow. ---- I would if I ___ to attend a meeting. A. don’t have B. didn’t have C. will not have D. would not have 11. If I had hurried, I ___ the train. A. would catch B. could catch C. would have caught D. had caught 12. If I had known that, I ___ so. A. wouldn’t do B. wouldn’t have done C. won’t do D. have not done 13. If I ___ you, I wouldn’t return the call. A. be B. am C. was D. we re 14. If the doctor had been available, the child ___. 教育是一项良心工程 1
Unit 4 一. if 条件句 if可以引导真实条件句和虚拟条件句。真实条件句表示在假设的条件下，能够实现的情况。在这种情况下，主句和从句的谓语动语随各自的人称和时态发生变化，同时if条件句遵循“主将从现”的原则，即主句用一般将来时，从句用一般现在时表将来。 If it doesn’t rain tomorrow, we will go for a picnic. 如果明天不下雨，我们去野餐。 如果if条件句用来描述说话人认为与事实相反的内容，或仅是一种愿望，假设、猜测等，我们称为虚拟条件句。 If I got rich , I would travel around the world. 如果我有钱了，我将周游全世界。 1. —I often get nervous when I have an English class. What should I do?
—If I were you, I . (ask the English teacher for help) 2. —What would the earth be like if there ?(is no air or water on it) —It could be like the moon without any living things. 3. If it ,the crops would be saved. (is to rain tomorrow) 4. If we had found him earlier, we .(solve the problem more easily) 5. If I hadn’t been so busy, I .(take part in the party) 四、单选。 ( )1. If my father here now, he tell me what to do. A. were, would B. were, will C. is would D. is will ( )2. If I a bee, I work much harder. A. were, would B. were, shall C. had, will D. have, should ( )3. If I much money, I buy a house. A. have, will B. had, would C. had, will D. have, should ( )4. He learn more quickly if he harder. A. will, work B. would , worked C. would, work D. will, worked ( )5. If I you, I do that. A. was, wouldn’t were, wouldn’t C. am, won’t D. were, won’t ( )6. It’s quite impossible that it will rain tomorrow. But if it ,I would still go to the park. A. should rains B. would rain C. rained D. had rained 五、汉泽英 1. 如果我是你，我会帮助她。If I you, I her. 2. 如果我以前去过那个地方，我就认识路了。（和相反） If I to the place before, I the way. 3. 万一你明天迟到了，我们就不等你了。（和相反） If you tomorrow, we for you.=If you late tomorrow, we for you. 4. 如果没有空气，地球上就不存在生物。 If there no air, there no living things.
iｆ引导的条件句中的虚拟语气?虚拟语气表示一种不能实现的 假设。该语法主要用于if条件状语从句。?一、ｉｆ引导的条件状语从句的分类及虚拟条件句的判断 1、可以把条件句分为两类： 1)．真实条件句（Sentences of Real Coｎdition）：凡是假设的情况发生性可能很大,就是真实条件句。例如:?⑴、If I ｈaｖe timｅ, I wｉll help yｏｕwith ｔhisｗork.如果我有时间会帮助你做此工作的。 (２)、Iｆtimｅperｍiｔs，ｗｅ＇ll go fishｉng tｏgetheｒ. (如果有时间的话，我们就一起去钓鱼。) 2).虚拟条件句（Seｎtｅnces of UnrｅaｌCoｎditiｏn):当假设是不大可能实现时，就是虚拟条件句。例如: ⑴、ＩfＩｗｅrｅyou ,I woｕｌd haｖe ａttenｄｅd th e meｅtiｎｇ．如果我是你的话，就去参加会议了。?⑵、I f ｈe had come ｈeｒe yesterday, ｈｅwouｌd haｖe sｅen ｈis ｏlｄfriｅnd.假如他昨天来这儿的话,就会看见他的老朋友。?⑴、If iｔｈaｄrained yｅsｔerday, we would hａve stayｅｄaｔｈｏme．(如果昨天下雨的话,我们就会留在家里。)?２、．ｉf条件状语从句中虚拟语气的判断?判断是真实条件句还是非真实条件句。只有在非真实条件句中才使用虚拟语气。通过句子意思，看假设的条件是否能够实现，能够实现是真实条件句，不能使用虚拟语气；假设的条件不能实现则是非真实条件句，要
用虚拟语气。?判断这个假设是与哪个事实相反。通常有三种情况:①与过去事实相反。②与现在事实相反。③与将来事实可能相反。 3、“后退一步法”?后退一步法是指在准确地判断了该句与哪一事实相反后，按虚拟语气的后退一步法处理从句谓语动词的时态。即：在非真实条件状语从句中,谓语动词按正常情况“后退一步”。也就是:?①与过去事实相反，在从句中用过去完成时形式表示。 ②与现在事实相反，在从句中用过去一般时形式表示。 ③与将来事实可能相反，在从句中用过去将来时形式表示。?主句中则用情态动词wｏuld, sｈouｌd, coulｄ等加一个与从句 一致的动词形式。例： ⑴、Ｉf I had coｍe ｈeｒyestｅrdａy，Ｉｗoｕlｄhave seen hiｍ. ⑵、Ｉf Ｉwｅｒe a teaｃhｅr, I ｗｏｕｌd bｅｓtrｉct wｉth my studenｔｓ. ⑶、Ｉｆit ｓhouｌd snow ｔomorｒow,ｔheｙcoulｄn't g o out. 4、注意事项?①iｆ条件句中如有ｗere，should, haｄ,可以省去if，并使用倒装语序。?②在现代英语中ｉｆ条件状与从句中的谓语动词如果是be其过去形式一般用wｅrｅ。 二、虚拟语气在ｉf 引导的条件句中的用法:?(一）、表示与现在事实相反的情况。其句子结构为：?从句:if + 主语+动词的过
虚拟语气用法 英语中的语气分为陈述语气、祈使语气、虚拟语气、疑问语气和感叹语气五类。 1、表示动作或状态是客观存在的、确定的或符合事实的，用于陈述句、疑问句和某些感叹句中。 China is an Asian country. (肯定句) How interesting my stay in China has been! (感叹句) 2、祈使句表示说话人对对方的请求、警告，建议或命令。如: Please come over here. 请到这边来。 Watch your steps! 当心!(走路) 3、虚拟语气表示说话者做出的假设而非事实，或难以实现的情况，甚至表达彻底相反的概念。此外，如需表达主观愿望或某种强烈的感情时，也可用虚拟语气。虚拟语气是由句中的谓语动词的特殊形式表示出来的。如: If I were a bird，I would be able to fly in the air. 如果我是一只小鸟，我就能在空中飞行。 I wish I could pass the examination. 我希望我能通过考试。
If there were a heavy snow next Sunday, we would not go skating. 如果下周日下大雪，我们就不能去滑冰了。 If she were to be here next Monday, I would tell her about the matter. 如果她下周一来这儿的话，我就会告诉她这件事的始末。 4、有时，虚拟条件句中，结果主句和条件从句的谓语动作若不是同时发生时，虚拟语气的形式应作相应的调整。这种条件句叫错综条件句。 ①从句的动作与过去事实相反，而主句的动作与现在或现在正在发生的事实不符。 If I had worked hard at school, I would be an engineer, too.如果我在学校学习刻苦的话，我现在也会成为一个工程师了 If they had informed us, we would not come here now. 如果他们通知过我们的话，我们现在就不会来这里了。 ②从句的动作与现在事实相反，而主句的动作与过去事实不符。 If he were free today, we would have sent him to Beijing. 如果他今天有空的话，我们会已经派他去北京了。 If he knew her, he would have greeted her. 要是他认识她的话，他肯定会去问候她了。 5、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，即把were, should, had等词置于句首，这种多用于书面语。 Should he agree to go there, we would send him there.要是他答应去的话，我们就派他去。 Were she here, she would agree with us.如果她在这儿的话，她会同意我们的。 Had he learnt about computers, we would have hired him to work here. 如果他懂一些电脑知识的话，我们已经聘用他来这里工作了。 【注意】 若条件从句为否定句，否定词not应置于主语之后，而不能与were，should，had 等缩略成Weren't，Shouldn't，Hadn't而置于句首。 Had it not been for the bad weather we would have arrived on time. 若不是天气坏，我们就准时到达了。 ②有时省略if后提前的had不是助动词: Had I time，I would come. 假若我有时间，我会来的。(=If I had time…) 6、非真实条件句中的条件从句有时不表达出来，暗含在副词、介词短语、上下文或其他方式表示出来，这种句子叫做含蓄条件句。 ①将条件会暗含在介词短语中，如without…, but for…,otherwise（要不是因为）等 But for his help, we would be working now. (要不是他的帮助，我们还会在工作呢。