作业帮英语语法,越多越好.
来源：学生作业帮 编辑：作业帮 分类：英语作业 时间：2024/05/11 12:27:25
英语语法,越多越好.
我有好多这样的语法.如果需要和我联络哦!
虚拟语气
虚拟条件句的形式与基本用法
一、虚拟条件句的形式.
虚拟条件句也叫非真实条件句,表现的内容与现实相反（这一点请与开放性条件句区别开来.）它构成虚拟的基本形式可见下表：
假设类型 从句 主句
与现在事实相反 If +主语+were或动词过去式 would主语+ should + docouldmight
与过去事实相反 If + 主语+had + 过去分词 would主语+should + have donecould might
与将来事实相反 were to+动词原形If + 主语 动词过去式should do would主语 should + do could might
虚拟条件句的基本用法
（1）与现在事实相反的假设.例如：
If all the sun’s heat reached the exterior of the earth, it would create tremendous destruction.
（2）与过去的事实相反.例如：
1. If the firemen had arrived earlier, they would have saved the house from burning.
2. He would have won the first prize if he had not slipped.
（3）与将来事实相反的假设
1. If he were to come next time, I would teach him a good lesson.
2. If you held your tongue from unkind speech, fewer people would be hurt.
（4）与将来事实可能相反的假设
1. If it should rain tomorrow, I would stay at home.
2. Should you get hungry, I have an extra sandwich.
虚拟语气的特殊表现形式
一、表示“好像”的表示形式.
除了 if条件从句外,由 as if和as though引导的状语从句表示方式时,意思是“好像”,
这时从句中的谓语动词应用虚拟语气.其动词形式用过去时（be用were的形式）表示所说的与现在的事实相反；用过去完成时表示所说的与过去的事实相反；用Would （could）+动词原形表示所说的动作可能在将来发生.
例如： 1. He spoke as if he had known everything about it.
2.You look as if you were well prepared.
3.She sounded as though she had been there.
注意： as if和 as though引导的从句不一定非用虚拟语气,要视假设的语气强弱而定.
尤其是在表示感觉的系动词后,如：look,seem,appear,sound,feel,smell,taste等,既可用虚拟,也可用直陈,且用直陈语气居多.
二、特殊连词的需要
连接词lest,for fear that, in case (以免) + 主语+should + 动词原形.在这类句子中,主
句均为正常句子.例如：
1. The government has decided to shut down game houses for fear that young people should be exposed to bad influences.
2. I am giving the boy severe punishment lest that he should make the same mistakes.
3. We did not tell her the bad news in case she should break down.
三、介词短语等其他方式表示虚拟.
有时假设的情况并不以条件从句表示出来,而是通过一个介词短语来表示,或通过上下文和其他方式表示出来.如but for, but that从句,in case of , on condition (that)( 在…条件下),on the understanding（that）(在…条件下), otherwise, supposing,With,Without等表示让步假设.它们引导的虚拟语气的形式与条件主句相同.
1．You could have passed unnoticed but for the few people who were sufficiently alert．
2. There would be no life without water and air.
3. He might have been killed but that the police arrived in time.
四、虚拟语气常用 If it were not for或were it not for这种说法说明为什么某事已经发
生或没有发生.用 If it had not been for或Had it not been for解释某事为什么在过去没有发生.以上的说法可以译为“要不是…”.注意were不能用was替代.
1. Were it not for your help,I would have been homeless and starved to death．
2. If it had not been for the disaster, my family would have had a happy time.
五、省略虚拟条件句.
虚拟条件从句中的谓语动词如果是were或should. had等词时,可以省略连词if,但要将were, should, had助动词移至主语前,形成句子倒装.
1. They firmly believed that a much stronger bridge could have been built had we
accepted their suggestions．
2．Should they forget to bring a compass with them, they would get lost in the woods．
3．Were she to go to New York again,she would visit the World Trade center.
4．Had it not for your help, we’d never had been able to get over the difficulty.
在从句中使用虚拟语气
一、 在wish的宾语从句中.对现在情况进行假设时从句使用一般过去时；对将来进行假设时从句使用过去将来时；对过去进行假设时,从句使用过去完成时.例如：
1. He is in Beijing. I wish he were here.
2. He was absent yesterday. I wish he had been here.
3. I wish you would come tomorrow.
二、在 would rather, would sooner, had rather等意为“宁愿、宁可、最好”的词或短语后面的从句中的谓语动词用过去式表示对现在或将来发生的动作的虚拟,用过去完成时形式表示对过去发生的动作的虚拟.例如：
1． I’d rather you did not take those important documents with you．
2． In rather you attended Professor Wang’s lecture next week
3． We blamed him because of his fault,but we would rather had not done so．
4．I would rather you go by train, since it’s much cheaper.
三、在某些特殊概念词的宾语从句中,一些表示提议、主张、要求、命令等概念的词语,由于它们本身隐含说话者的主观意见,认为某事应该或不应该怎样.这些词后面的that从句应用虚拟语气,且均以“should”表示这种语气,但事实上“should”常被省略,故此从句中的谓语动词用原形.这些词可分为下列几类：
（一） 下列动词后“that”引导的宾语从句,如：
suggest（建议）, Propose（提议）,recommend（建议）,move（提议）,advise（建议）insist（坚持）； urge（极力主张）, ask,require, request（要求）, demand, desire,order,command（命令）,decide,intend（打算）,prefer（宁愿）等.例如：
1. The committee requested that they be on time for the project.
2. He insisted that you go with them.
3. The doctor suggested that he give up drinking.
4. The public urged that the issue be settled immediately.
5. He asked that he be given one more chance.
6. I prefer that you not go.
7. She recommended that you take French instead of Russian.
8. She advised that I rest in bed for a few days.
虚拟语气
虚拟条件句的形式与基本用法
一、虚拟条件句的形式.
虚拟条件句也叫非真实条件句,表现的内容与现实相反（这一点请与开放性条件句区别开来.）它构成虚拟的基本形式可见下表：
假设类型 从句 主句
与现在事实相反 If +主语+were或动词过去式 would主语+ should + docouldmight
与过去事实相反 If + 主语+had + 过去分词 would主语+should + have donecould might
与将来事实相反 were to+动词原形If + 主语 动词过去式should do would主语 should + do could might
虚拟条件句的基本用法
（1）与现在事实相反的假设.例如：
If all the sun’s heat reached the exterior of the earth, it would create tremendous destruction.
（2）与过去的事实相反.例如：
1. If the firemen had arrived earlier, they would have saved the house from burning.
2. He would have won the first prize if he had not slipped.
（3）与将来事实相反的假设
1. If he were to come next time, I would teach him a good lesson.
2. If you held your tongue from unkind speech, fewer people would be hurt.
（4）与将来事实可能相反的假设
1. If it should rain tomorrow, I would stay at home.
2. Should you get hungry, I have an extra sandwich.
虚拟语气的特殊表现形式
一、表示“好像”的表示形式.
除了 if条件从句外,由 as if和as though引导的状语从句表示方式时,意思是“好像”,
这时从句中的谓语动词应用虚拟语气.其动词形式用过去时（be用were的形式）表示所说的与现在的事实相反；用过去完成时表示所说的与过去的事实相反；用Would （could）+动词原形表示所说的动作可能在将来发生.
例如： 1. He spoke as if he had known everything about it.
2.You look as if you were well prepared.
3.She sounded as though she had been there.
注意： as if和 as though引导的从句不一定非用虚拟语气,要视假设的语气强弱而定.
尤其是在表示感觉的系动词后,如：look,seem,appear,sound,feel,smell,taste等,既可用虚拟,也可用直陈,且用直陈语气居多.
二、特殊连词的需要
连接词lest,for fear that, in case (以免) + 主语+should + 动词原形.在这类句子中,主
句均为正常句子.例如：
1. The government has decided to shut down game houses for fear that young people should be exposed to bad influences.
2. I am giving the boy severe punishment lest that he should make the same mistakes.
3. We did not tell her the bad news in case she should break down.
三、介词短语等其他方式表示虚拟.
有时假设的情况并不以条件从句表示出来,而是通过一个介词短语来表示,或通过上下文和其他方式表示出来.如but for, but that从句,in case of , on condition (that)( 在…条件下),on the understanding（that）(在…条件下), otherwise, supposing,With,Without等表示让步假设.它们引导的虚拟语气的形式与条件主句相同.
1．You could have passed unnoticed but for the few people who were sufficiently alert．
2. There would be no life without water and air.
3. He might have been killed but that the police arrived in time.
四、虚拟语气常用 If it were not for或were it not for这种说法说明为什么某事已经发
生或没有发生.用 If it had not been for或Had it not been for解释某事为什么在过去没有发生.以上的说法可以译为“要不是…”.注意were不能用was替代.
1. Were it not for your help,I would have been homeless and starved to death．
2. If it had not been for the disaster, my family would have had a happy time.
五、省略虚拟条件句.
虚拟条件从句中的谓语动词如果是were或should. had等词时,可以省略连词if,但要将were, should, had助动词移至主语前,形成句子倒装.
1. They firmly believed that a much stronger bridge could have been built had we
accepted their suggestions．
2．Should they forget to bring a compass with them, they would get lost in the woods．
3．Were she to go to New York again,she would visit the World Trade center.
4．Had it not for your help, we’d never had been able to get over the difficulty.
在从句中使用虚拟语气
一、 在wish的宾语从句中.对现在情况进行假设时从句使用一般过去时；对将来进行假设时从句使用过去将来时；对过去进行假设时,从句使用过去完成时.例如：
1. He is in Beijing. I wish he were here.
2. He was absent yesterday. I wish he had been here.
3. I wish you would come tomorrow.
二、在 would rather, would sooner, had rather等意为“宁愿、宁可、最好”的词或短语后面的从句中的谓语动词用过去式表示对现在或将来发生的动作的虚拟,用过去完成时形式表示对过去发生的动作的虚拟.例如：
1． I’d rather you did not take those important documents with you．
2． In rather you attended Professor Wang’s lecture next week
3． We blamed him because of his fault,but we would rather had not done so．
4．I would rather you go by train, since it’s much cheaper.
三、在某些特殊概念词的宾语从句中,一些表示提议、主张、要求、命令等概念的词语,由于它们本身隐含说话者的主观意见,认为某事应该或不应该怎样.这些词后面的that从句应用虚拟语气,且均以“should”表示这种语气,但事实上“should”常被省略,故此从句中的谓语动词用原形.这些词可分为下列几类：
（一） 下列动词后“that”引导的宾语从句,如：
suggest（建议）, Propose（提议）,recommend（建议）,move（提议）,advise（建议）insist（坚持）； urge（极力主张）, ask,require, request（要求）, demand, desire,order,command（命令）,decide,intend（打算）,prefer（宁愿）等.例如：
1. The committee requested that they be on time for the project.
2. He insisted that you go with them.
3. The doctor suggested that he give up drinking.
4. The public urged that the issue be settled immediately.
5. He asked that he be given one more chance.
6. I prefer that you not go.
7. She recommended that you take French instead of Russian.
8. She advised that I rest in bed for a few days.