| 虚拟语气 | 用来表示说话人所说的并不客观存在的事实，而是一种主观愿望、建议或与事实不符的假设、猜疑、怀疑或推测。由句中的谓语动词的特殊形式表示出来 |
| If I Were a bird, 1 would be able to fly in the air.如果我是一只小鸟，我就能在空中飞行。 |
| 从句 | 主句 | 例句 | | 与现在事实 相反 | If +主语 + 动词一般过去时(did/Be用were) | 主语+should/would/might/could +do （动词原形） | If I were you,I would take an umbrella 如果我是你，我会带把伞 | | 与过去事实 相反 | If +主语 + had done （过去完成时） | 主语+should/would/might/could +have done（现在完成时） | If I had got the earlier,I should/would have met her如果我早到那儿，我就会见到她 | | 与将来事实 相反 | if +主语 + did /were | 主语+should/would/might/could +do （动词原形） | If he should come here tomorrow,I would talk to him如果他明天来这儿的话，我就跟他谈谈 |
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| 虚拟语气8种固定句型 | 1. Would you mind +主语 +谓语虚拟 | 您是否介意... |
| 2. would rather (that)主语 +谓语虚拟 | 宁愿去做 |
| 3. It is high time that sb. did / (should) do sth. | 到某人做某事的时间 |
| 4. It is necessary/important/essential/strange/natural/advisable that sb. (should) do sth. | 某人有必要的/很重要的/必不可少的/奇怪的/自然的/有建设性的去做某事.... |
| 5. It is a pity/ duty/shame/ regret that sb. (should) do sth. |
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| 6. But for/Without + sth. +主语 + 谓语虚拟 | 要不是... |
| 7. If only + 主语 + 谓语虚拟 | 要是...就好了 |
| 8. 主句+ as if/as though + 主语 + 谓语虚拟 | 就好像... |
1. 用if条件从句表示的虚拟条件 | ① 虚拟现在时表示与现在事实相反的假设，if 从句的谓语形式用动词的过去式(be一般用were)，主句would/should/could/might+动词原形 | | 是虚拟条件最普通的方式 | If I were in your position I would marry her. |
| ② 虚拟过去时表示与过去事实相反的假设，if 从句的谓语形式用过去完成时即had＋过去分词，主句用would should coul/ might + have +过去分词 | | If it had not rained so hard yesterday we could have played tennis. | | ③ 大多数的虚拟条件句属于上面三种情况的一种，但并不排除存在条件和后果中，一个和现在情况相反，另一个和过去情况相反 | | If you had followed what the doctor said, you would not have been so painful now.这个句子在高中出现频率颇高 | | ④ 但是，如果后果用了虚拟语气，而条件却用陈述语气，这种用法是错的。 |
| 2. 除表示虚假条件外，if从句还可以表示对将来的推测，由于是将来还没有发生的，所以谈不上是真实的还是虚假的，只能说这个事情发生的可能性有多大。 | | 一般情况下，可以用陈述语气的if从句来表示对一个未来事实的推测，这个事实是完全可能发生的。 | | If从句的谓语形式用一般过去式或用were to / should +动词原形，主句用would / should /could/ might +动词原形 | | Jean doesn't want to work right away because she thinks that if she were to get a job she probably wouldn't be able to see her friends very often. | | 3. 有时可把含有助动词、情态动词、be或have的虚拟条件句中的连词if 省去，而将had , should, were 等词提到主语之前，即用倒装结构,这时候如果出现not等否定词，否定词需放在主语后面 | | 这种结构口语中很少用，但各类考试出现频率高：If it had not rained so hard yesterday we could have played tennis.→Had it not rained so hard yesterday, we could have played tennis. | | 4. 大多数的虚拟条件通过上面所讲的两种方法表达，但在个别句子中也可以通过介词without和介词短语but for表达，副词otherwise等表达出来。 | | 例如：We didn't know his telephone number; otherwise we would have telephoned him. | | 值得注意：包含but for的句子，谓语动词必定要用虚拟形式，但包含without等短语的句子，谓语动词未必一定要用虚拟语气。 |
| 用在宾语从句中的虚拟语气 | 1. 在表示愿望的动词wish后的宾语从句中，需用虚拟语气。（wish后的that 常省略），根据主句时态，从句谓语时态相应退后一位，例：How she wished his family could go with him. |
| 2. 在具有愿望、请求、建议、命令等主观意愿的动词(desire, demand, advice, insist, require, suggest, propose, order, recommend, decide …) 后的宾语从句中需用虚拟语气。 |
| 谓语动词用(should) +动词原形。值得注意的是，如果宾语从句的动词是否定的，否定词not的位置应在动词之前，而不是动词之后。 |
| 例如：The head nurse insisted that the patient not be move. |
| 另外suggest表“暗示”，insist表“坚持某种说法”时，后面的从句不用虚拟语气，例：Her pale face suggests that she is ill.或He insisted that he did not kill the boy. |
| ① 在It is+上述动词的过去分词，其后所跟的主语从句中，如It is suggested that pupils wear school uniforms. |
| ② 在上述动词相应的名词形式作主语+连系动词，其后的表语从句中，例如His suggestion was that classed be re-scheduled. |
| ③ 在对上述动词相应的名词进行解释的同位语从句中，如：The workers raised the demand that their pay be increased to cope with the inflation. |
| 其它形式的虚拟语气 | 1. it is +necessary等形容词后，that主语从句中虚拟形式使用，这类形容词包括necessary, important, essential, imperative, urgent, preferable, vital, advisable等 |
| 例如It is necessary that you listen to the teacher carefully.或者It is essential that you be able to pronounce every single word correctly. |
| 2. 在It's (high/about) time 之后的定语从句中需用虚拟语气。谓语动词用过去式，例如It is high time that you went to school |
| 3. 虚拟语气在as if / as though 引导的方式状语从句中的应用（谓语动词形式与wish后的宾语从句基本相同）表示与现在事实相反或对现在情况有怀疑，谓语动词用过去式。 |
| 例如：He felt as if he alone were responsible for what had happened. 表示过去想象中的动作或情况，谓语动词用过去完成式。 |
| 4. 在lest 引导的状语从句中，谓语动词多用虚拟语气，(should )+ 动词原形。例如： The mad man was put in the soft-padded cell lest he injure himself. |
| 5. 在if only 引起的感叹句中需用虚拟语气。谓语动词用过去式或过去完成式。例如： Look at the terrible situation I am in! if only I had followed your advice. |
| 从句 | 主句 | 从句 | 主句 | 例句 | | 与现在事实 相反 | did /were | would/should/could/might+do | If+主语 一般过去时（Be用were | 主语+should/would/might/couldt +do | If I were you,I would take an umbrella 如果我是你，我会带把伞 | | 与过去事实 相反 | had done | would/should/could/might+have done | If+主语 + had done | 主语+should/would/might/couldt +have done | If I had got the earlier,I should/would have met her如果我早到那儿，我就会见到她 | | 与将来事实 相反 | did /were | would/should/could/might+do | if+主语 + were to do | 主语+should/would /might/couldt +do | If he should come here tomorrow,I would talk to him如果他明天来这儿的话，我就跟他谈谈 |
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