英语条件从句的几种特殊表达法及练习

1、英 语条 件 从 句的几 种 特殊表 达 法虚拟语气 是高中英 语教学 中的一 个 重点， 又是一 个难 点。 在 虚拟语气 的句子中，条 件 从 句的表示方法较 多 ，（ 1） 表示 与现 在事 实 相反的假 设 ， 条 件 状语从 句中的 谓语动词 用 "过 去式 （ be 动词 的 过 去式用 were） "，而主句中的谓语动词用 "would / should/ could /might + 动词 原形 "。如：If I were a boy, I would join the army.If the had time, she should g

2、o with you.（ 2）表示 与过 去的事 实 相反， 条 件 状语从 句中的 谓语动词 用 过 去完成 时 ， 主句中的谓语动词则用 "would / should / might / could + have + 过 去分 词 "。如：If he had taken my advice, he would have succeeded in the competition.（ 3）表示 与将来 事 实 相反， 条 件 状语从 句中的 谓语动词 一般 过 去 时 或 should（were to） + 动词 原形，而主句中的谓语动词则用 would / should

3、/could might + 动词 原形。如；If it were to rain tomorrow, the football match would be put off.在有些情 况 下 ，条 件 从 句也可用其他方法来 表示 。 下面 谈 几 种条件 从 句的特殊表达 法。一、混合 虚拟条 件句如果 条 件 从 句的 动 作和主句的动 作不是同 时发 生， 主句和 从 句的 谓语动词 的形式 应 分 别 根据各自所表示的时间 加以 调 整。 这种 句子叫做混合虚拟条 件句。如：If he had followed my advice,he would be quite all righ

4、t now. （ 从 句述 说过 去，主句述说现 在）If China had not been liberated,the working people would still be leading a miserable life. （ 从 句表示 与过 去的事 实 相反，主句说 明 与现 在的事 实 相反）二、省略if 的倒装 条 件句如果 条 件 从 句的 谓语动词 包含有 were 或助 动词 、情 态动词 had,should,could ，有 时 可 将连词 if 省去，而 将 条 件 从 句的主 语 置于 were,had,should,could 之后。 这种 用法主要用于书

5、 面 语 ，如：Were I（=If I were）in your place,I wouldn't give it up soearly.Had I(=if I had)known,I might have joined you in thediscussion.Should you(=If you should)be interested,I have a book onthe subject you might like.三、省略主句，只保留if(only) 的 条 件句虚拟条 件句中的表示结 果的主句有时 形式上可以省略，但意 义 仍然存在。这种 句子只保留一个 if(only

6、) 条 件 从 句，表 达说话 人的强烈愿望。如If(only)shewere my sister ！ 她 是我的妹妹就好了！四、含蓄 虚拟条 件句有 时虚拟条 件句不用 条 件 从 句，而是通过 上下文或用介词 短 语 等表示出 来 。这种 句子叫做含蓄虚拟条 件句 。下面列 举 几 种 。1. 在主语词组 中表示含蓄条 件(1) 主 语 是 动词 不定式短 语 ，表示含蓄条 件。It would be good to leave the matter in his charge. 如果把 这 件事 让 他 负责 就好了。该 句可改 写 成： It would be good if we c

7、ould leave the matter in his charge.(2) 主 语 是 动 名 词 短 语 表示含蓄 条 件。Doing the work in that way would have cost much more time and money.如果用那 种 方法做 这项 工作就 会 耗 费 更多的 时间 和金 钱 。该 句可改 写为 ： If we had done the work in that way, it would have cost much more time and money .(3) 主 语 中 带 有定 语从 句表示含蓄条 件。A man who

8、is always thinking of others would not have done such a thing.如果一 个 人 总为别 人着想 ，他就不 会 做出 这种 事情 来 。(4) 主 语 中含有作定语 的分 词 或形容 词 表示含蓄 条 件。Anyone being his position would have made no reply. 任何人 处 在他那 个 位置，都不会 回答的。该 句可改 写为 ： If anyone had been in his position he would have made no reply.A less complicated

9、problem would have easily been solved. 如果 问题 不是很 复杂 的 话 ，那 么 就很容易解 决 了。该 句可改 写为 ： If the problem had been less complicated, it would haveeasily been solved.2. 用介词 短 语 表示含蓄 条 件We could have done better under more favorable conditions.如果在更好的条 件下，我 们会 干得更好。此句可改写为 ： If the conditions had been more favor

10、able, we couldhave done better.This change could not have taken place without a solid industrial foundation.如果 没 有 坚 定的工 业 基 础 ， 发 生 这样 的 变 化是不可能的。此句可改写为 ： If it had been without a solid industrialfoundation, this change could not have taken place.3. 用 but 或 but for 引 导 含蓄 条 件句（ but 后跟 从 句， but for

11、后跟短 语 ）But for your help,our experiment wouldn't have been so successful.假如 没 有 你们 的 帮 助，我 们 的 实验 是不 会 如此成功的。But for the storm,we should have arrived earlier.要不是 碰 到暴雨我 们会 到得早一些。We would have invited them to the dance, but they were too busy.要不是他 们 太忙，我 们会 邀 请 他 们来参 加舞 会 的。此句可改写为 ： If they had n

12、ot been so busy, we would have invitedthemto the dance.But that he is in hospital, he would go abroad for his summer vacation.要不是生病住院，他就出国 度暑假了。该 句可改 写为 ： If he were not in hospital, he would go abroad for his summer vacation.真实条 件 从 句 与虚拟条件 从 句的 区别if 既 可引 导 一 个真实条件 状语从 句又可引 导 一 个 非 真实条 件 状语从 句， 二者主

13、要在以下三个 方面有所不同：1、 意 义 及 谓语动词 形式不同如果 该条 件 纯属 假 设 ， 谓语动词 用 虚拟语气 ； 有可能 实现 的 条 件 则 使用 动词通常的 陈 述形式：1 . 非 真实条 件 状语从 句的 谓语动词 用 动词过 去式 来 表示 与现 在事 实 相反或 难以实现的愿望，主句则用“would+动词原形”；而真实条件状语从何的谓语动词 用 动词 的一般 现 在 时 表示一般或未来 情形下的 条 件， 主句用一般现 在 时 或 将来时。试比较：If my husband were a woman, he would understand my feelings a b

14、it better. 如果我丈夫是个 女人的 话 ， 他就 会 更好一点 儿 理解我的感情了。（丈夫不可能是女人）Oil floats if you pour it on water. 如果 你 把油倒在水上，它 就漂浮在上面。（能 实现 的事 实 ）2 .非真实条件状语从何的谓语动词用“had+±去分词"表示与过去的事实 相反，主句用“would have done ”； 真实条 件 状语从 句用一般 过 去 时 指 过 去的事实 或用于 间 接引 语 中 （可表示 过 去 将来 的情 况 ），主句用一般过 去 时 或 过 去 将来时。试比较：If I had been

15、a teacher at that time, I would have argued with him.当时 我要是老 师 的 话 ，就和他 争辩 了。 （事 实 上 当时 不是老 师 ）If Mike was a liar, it was for my sake. 如果 麦 克曾 经 是 个 撒 谎 的人，那也 是 为 了我。（当时麦克 极 有可能是撒了谎 ）He said he would go there if it was fine the next day. 他 说 ，如果第二 天天 气 好他就去那里。2、 从 句所接的情态动词 的含 义 不同1. if I （we, you, h

16、e.） +“should 祠原形”或 “ were to 呦词原形”或动词过 去式， 表示 对将来 情 况 的 虚拟 假 设 ， 即某事不 会 或不太可能发 生， 具有 较大的 试 探性。如：If you should run into Peter, please tell him he owes me a letter.假如你碰见 皮特，告 诉 他他 该给 我 写 信了。What would you do if war were to break out? 如果 战争 爆 发 ， 你会怎么 办？2. if 引 导 的 真实条 件 状语从 句一般很少使用将来时态 ， 但有 时 也可用情 态动词

17、will或would来表示“愿望”（如果愿意甚至可用这种方式提出请求。如：It'll make me very happy if you'll accept it. 如果 你 愿意收下它 我 会 很高兴 的。If you will wait a moment, I'll go and tell the manager that you are here. 如果 你 愿意等一 会儿 ，我就 会 去告 诉经 理 你来 了。If you will hold my bag, I'll open the door （i.e. please hold my bag）.如果

18、你 愿意替我拿包，我就开门（即，请 替我拿包）。3、 与 其他句型的转换 不同1. 非 真实条 件 状语从 句中的 if 可省略， 从 句可以用倒装语 序； 而 真实条 件 状语从 句一般不可以。如：If he were my son, I would beat him. 如果他是我的儿 子我就打他。fWere he my son, I would beat him. ( V)If you touch me again, I'll call the police.你再碰我，我就叫警察。fDoyou touch me again, I'll call the police. (x

19、)2. 真实条 件 状语从 句可以 转换为 “祈使句 +and + 陈 述句”，而非 真实条 件 状 语从 句 则 不可以。如：If you touch me again, I'll call the police.f(You) Touch me again andI'll call the police. ( V)3. 真实条 件 状语从 句的否定式可与 unless . 转换 ， 而非 真实条 件 状语从 句的否定式却不能。如：If it doesn't rain tomorrow, I'll plant the flowers. 如果明天不下雨，我就 把花

20、栽上。I'll plant the flowers unless it rains tomorrow. (V)If it hadn't been for you, I would have failed in the exam. 如果不是你 的话我就不会通过考试了。 Unless it had been for you, I would have failed in the exam. ( x ) 虚拟语气练习题1. If there were no subjunctive mood, English _ much easier.A will beB would have be

21、enC could have beenD would be2. If she had worked harder, she .A would succeed B had succeededC should succeed D would have succeeded3. If my lawyer here last Saturday, he me from going.A had been; would have preventedB had been; would preventC were; would preventD were; would have prevented4. Witho

22、ut electricity human life quite different today.A is B will be C would have been D would be5. - If he , he that food.-Luckily he was sent to the hospital immediately.A was warned; would not takeB had been warned; would not have takenC would be warned; had not takenD would have been warned; had not t

23、aken6 I didn t see your sister at the meeting. If she ， she would have metmy brother.A has come B did come C came D had come7 You didn t let me drive. If we _ in turn, you _ so tired.A drove; didn t getB were driving; wouldn t getC drove; wouldn t getD had driven; wouldn t have9 Had you listened to

24、the doctor, you _ all right now.A are B were C would be D would have been10 I be free tomorrow, I could go with you.A could B should C might D must11 _to do the work, I should do it some other way.A If were I B I were C Were I D Was I12 today, he would get there by Friday.A would he leave B was he l

25、eavingC were he to leave D if he leave13 your letter, I would have writer back two days ago.A If receivedB Should I receiveC Had I receivedD If I could have received14 , he would have passed the exam.A if he were to study B if he studied hardC had he studiedD should he study hard15 Should it rain, t

26、he crops _.A would be savedB would have been savedC will be savedD had been saved16 If I you, I would try again.A am B was C were D be17 , all the students would hear.A If the teacher had spoken louder B If the teacher will speak louder C Had the teacher spoken louderD If the teacher spoke louder18 What should we do if it tomorrow?A should snow B would snowC snowD will snow19 If you 5 minutes earlier, you _ him.A come; will seeB had come; would have seenC should come; had seenD came; would see20 You _ such a serious mistake if you had followed his advice.A may not makeB might have not ma