请问在虚拟语气中,若要表示与现在事实相反 主句与从句都应该使用什么时态

虚拟语气(Subjunctive Mood)这一语法项目是各类英语考试中心测试的重点之一.虚拟语气是一种特殊的动词形式,用来表示说话人所说的话并不是事实,而是一种假设、愿望、怀疑或推测.
Ⅰ用以表示虚拟条件的虚拟语气
⒈ 用if条件从句表示的虚拟条件,是虚拟条件最普通的方式.
① 虚拟现在时表示与现在事实相反的假设,其if 从句的谓语形式用动词的过去式(be 一般用were),主句用would/ should/ could/ might +动词原形,例如：If I were in your position I would marry her.
② 虚拟过去时是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 / could / might + have +过去分词,例如：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,例如：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.
⒉ 除了表示虚假条件外,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,例如：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.（1996年1月四级第44题）
⒊ 有时可以把含有助动词、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.这种结构在口语中很少使用,但频频出现在各类考试中出现,例如：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.
⒋ 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.（1995年6月四级第46题）值得注意的是,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.
⒌ 有时虚拟条件不是明确地表达出来,而在蕴含在用but引导的从句里,于是便出现了有谓语动词是虚拟语气的主句加上谓语动词是陈述语气的but从句构成的并列复合句,例如I would have hung you but the telephone was out of order.在这样的句子里,如果主句没有用虚拟语气,或者从句用了虚拟语气,都是错的.
Ⅱ用在宾语从句中的虚拟语气
⒈ 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,例如：How she wished his family could go with him.
⒉ 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,如suggest表达“暗示”,insist表示“坚持某种说法”时,后面的从句不用虚拟语气,例如：Her pale face suggests that she is ill.或He insisted that he did not kill the boy.
除此之外,上述动词也要求用虚拟式
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.
⒊ would （had）rather , would sooner也用来表达主观愿望,它们之后的宾语从句中需用虚拟语气.谓语动词用过去式表示现在或将来,用过去完成式表示与过去事实相反,例如：I would rather he went right now.
Ⅲ其他形式的虚拟语气
⒈ 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.
⒉ 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
⒊ 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.
⒋ 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.（1998年1月四级第38题）
⒌ 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.
虚拟语气是一种动词形式,表示说话人的一种愿望,假设,怀疑,猜测, 建议等含义,虚拟语气所表示的含义不是客观存在的事实.
If I were you, I'd take them away.
如果我是你的话,我就会带走他们.
If I had met Li Hua, I could had told him.
如果我碰见了李华,我就告诉了他了.
If I had time. I could come to help you.
如果我有时间,我会来帮助你的.
He suggested that our class should be divided into five groups.
他建议说我们的班应该分成五个小组.
He speaks to us as if he had been there.
他给我们讲的好象他去过那儿.
虚拟语气的用法
1) 虚拟语气用在简单句中,表示祝愿,命令.
May you be happy.
祝你幸福.
May you have a good time.
祝愿你玩的痛快.
May the friendship between us last long.
祝愿我们的友情天长地久.
Have a good journey!
祝愿你旅途愉快!
You go out!
你出去!
2) 虚拟语气用在宾语从句中.动词 wish, suggest,order,insist, propose,等词后面的宾语从句表示的是一种虚拟语气, 宾语从句中的动词动作表示的只是一种愿望,要求.
I wish she would be on my side.
我希望她能站在我一边.
I wish I could help him.
我希望我能帮助他.
He insisted that all of us should be there on time by any means.
他坚持要我们大家想尽办法按时去那儿.
动词 demand, suggest, order, insist, propose 后面的从句中,"should" 可以省略.
The teacher suggested that we (should) clean the blackboard after class.
老师建议我们课后把黑板擦了.
He ordered that the students wash the clothes every week by themselves.
他要求学生每周都要自己洗衣服.
3) 虚拟语气用在主语从句中.
在句型 "It is important (necessary, strange, natural) that . " 中,that 后面的从句中的谓语动词用： should + 动词原形
It's necessary that we should have a walk now.
我们有必要出去散散步.
It's natural that she should do so.
她这样做是很自然的.
It's important that we should take good care of the patient.
重要的是我们要照顾好病人.
4) 虚拟语气用在状语从句中.
虚拟语气最多地用在表示条件的状语从句和表示结果的主句中.在表示与事实相反的虚拟语气时,动词有三种时态形式,即现在,过去和将来.
与现在事实相反的：
条件从句 结果从句
If I (we,you,he,they)+ 动词过去式.. if I (he,she) were... I (we) should + 动词原形. He (you,they) would + 动词原形.
与过去事实相反的：
条件从句 结果从句
If I(we,you,he,they)+ had + 过去分词 I(we)should + have+ 过去分词.He (you,they) would + have + 过去分词.
If I were you, I should buy it.
如果我是你,我就买了它.
If I had time, I would study French.
如果我有时间,我会学习法语的.
If she knew English,she would not ask me for help.
如果她懂英语的话,她不会找我帮忙的.
If you had got up earlier, you could have caught the train.
如果你早一点起床,就会赶上火车的.
If it were fine tomorrow,I would go shopping.
如果明天天气好,我就去买东西.
有关虚拟语气的几个问题：
1) 有时if引导的状语从句可以省略 if,而把从句中的动词 were, had 或 should 移到主语前面.
Were she younger, she would do it .
如果她年青点, 她就会干的.
Had he known her address, he would had gone to visite her.
如果他知道她的地址,他会去看她的.
2) 有时表示虚拟语气的条件从句或者主句都可以省略,而只剩下一个主句或者一个条件从句.
I could help you.
我本来可以帮助你.
If I had time.
我要有时间该多好啊.
She should have come to the party.
她应该来参加聚会.
If he had much more money.
如果他有更多的钱就能.
3) 虚拟语气中,条件从句的动词动作可以和主句的动词动作时态不一致.
If they had studied hard, they could do it easily now.
如果他们以前努力学习的话,现在干的就会容易些.
If he had not taken my advice, he wouldn't do it much better like this.