1."在虚拟语气中,如果主句是过去完成时,从句是would do还是would have done? "， 当然要用would have done.
2.这两个句子的意思不一样，主句，从句的时态一定要对应。
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虚拟语气在英语里主要用来表达：
　　 a. 非真实的情景，不可能发生的事，即某种与事实相反或难以实现的情况，或说话人主观愿望。


　　b. 与客观事实相反地情景， 即强制性虚拟语气，表示建议、命令、劝告这一类的意思上，表示强烈的要求做到、必须做到这样的含义。


　　虚拟语气的表达形式是通过动词的变化形式表达的， 其特点是主从句时态的不一致， 而且一般有明显得标志。具体考点如下：


　　考点一：if 句型 (共有三种句型)


　　1. 与现在的事实相反：


　　从句用一般过去时，主句的谓语用would (could, might) ＋动词原形


　　If I were Bill Gates, I would not work so hard every day.


　　2. 与过去的事实相反：


　　从句用过去完成时，主句的谓语用would (could, might) ＋ 现在完成时


　　If I had gone to America when I graduated from middle school, I would have got my PhD degree.


　　3. 与将来的事实相反：


　　从句用should (were to，did) + 动词原形，主句的谓语用would (could, might) ＋动词原形


　　If it should/were to snow tomorrow, I would go skiing.


　　 4. 虚拟语气条件句中if的省略，此时主谓要倒装。


　　 Had he worked harder, he would have got through the exam.


　　5. 条件句发生的动作和主句发生的动作不一致，(例如：条件句动作发生在过去，主句的动作发生在现在)谓语动词要根据表示的时间进行调整。


　　If you had taken the medicine yesterday, you would feel much better now.


　　If I were you, I wouldn’t have missed the film last night.


　　考点二： wish 句型 表达“但愿…，要是…多好”的语气


　　 wish后宾语从句用虚拟语气，其谓语部分有时态变化：表示对现在情况珠虚拟时，动词用一般过去时(如did)；对过去的情况进行虚拟时，动词用“过去完成时(如had done)或情态动词的过去时 + 动词的现在完成时(如could have done)”形式；表示情况的虚拟时，用“情态动词的过去时形式 + 动词原形(如might do)。”


　　I wish I had been to the concert last night.


　　I wish he would forgive me.


　　I wish I would remember all the English words in a week.


　　同例： 在as if /as though引导的状语从句中和以 if only引起的感叹句中，谓语动词与wish引导的宾语从句中的虚拟形式相同。例：


　　He talked as if he had known Tom for a long time.


　　He talks as if he were the boss. 他说起话来就像他是老板。


　　If only I were free now. (注意： if only…后面可以不加主句 )


　　考点三：在强制性语气的宾语从句中， 即表示建议、命令、劝告、决心等主观色彩的动词 + that + (should) + 动词原形， 其中should 经常被省略。这类动词包括：


　　suggest, propose, recommend, demand, order, command, desire, require, insist, advise, decree (发布命令；下令), determine, prefer, stipulate, move(动议，规定)，direct(命令)，maintain(坚持)，decide，ask


　　I suggest that you (should) not be late again next time.


　　I prefer that you ( should ) not do that. 我认为你还是别干那件事的好。


　　注意一： 以上动词转化为名词(如：suggestion, proposal, demand, order, command, advice, desire, requirement, request, agreement, determination, preference , resolution, indication 等)后接同位语从句或表语从句时，从句要求用虚拟语气，其谓语部分用“(should)+ 动词原形” (should可省略)。


　　We are all for your proposal that the discussion be put off.


　　His demand is that all of us (should) be present at the meeting.


　　注意二：以上这类动词中有时候有的动词的宾语从句不用虚拟语气，必须根据句子的意思来判断。


　　 What he said suggested(表明)that he did not agree with us.


　　考点三：It is/was + 形容词 / 过去分词 + that + (should) + 动词原形，这些形容词主要表示必要性、重要性、强制性、合适性、义务性，即某人对某事的反应。


　　important, natural, desirable, possible, astonishing, advisable(可取的， 明智的), anxious, appropriate, compulsory(义务的；强制的；强迫的), crucial (至关紧要的), eager, essential, fitting, imperative (命令的， 强制的， 必要的), improper, natural, necessary, obligatory (义不容辞的， 必须的), preferable, proper, urgent, vital, willing shocked, requested


　　It was essential that the application forms be sent back before the deadline.


　　 It is requested that a vote be taken. 有人提请投票表决。


　　It is necessary that we all should do our best to protect environment around us.


　　注意：表示不可思议、滑稽、不可想象、令人吃惊这样的形容词如amazing, strange, odd, ridiculous, surprising, unthinkable，incredible等后的that从句中should一般不省略，而且翻译为“竟然”， 表示说话人的惊异、懊悔、失望等情感。


　　 It is surprising that they should pass the time like that.


　　 It is incredible that Jane should have finished her paper so soon.


　　 It is strange that there should be any hope of finding the lost child.


　　考点四：在 would rather…， would sooner…， had rather…， would just as soon…， would prefer… 意为“宁可，但愿”。从句用虚拟语气，若表示现在或将来的事情，谓语用过去时；若表示过去的动作，用过去完成时。


　　 I would rather that you painted the room green.


　　 I’d just as soon you had returned the book yesterday.


　　考点五：It’s (about/high/ good ) time that…，表示“该是。。。的时候了”， 含有 “晚一点” 的意思， 表示建议现在应该做什么事，从句一般用一般过去时。


　　It’s time you went to bed.


　　It’s high time that we took action.


　　考点六：在lest that …， for fear that…， in case that … 引导的表示消极意义的目的主语从句中常用虚拟语气，表示“唯恐，以免”，从句用 should +动词原形。


　　 He put his coat over the child for fear (lest )that he should catch cold.


　　He emphasized it again and again lest she (should) forget.


　　Take a hat with you in case the sun is very hot (注意：该句陈述某一事实)


　　考点七：含蓄虚拟条件句


　　含蓄虚拟条件句是指没有出现由if引导的条件句，而条件句的意思是用其他方式表达的。 如：without, but for, otherwise，or, but that, given, provided, supposing, were it not for等等。


　　Without your help, we couldn’t have finished the work on time.


　　 But for the English examination I would have gone to the concert last night.


　　I wouldn't have succeeded without your help.


　　We didn’t know his telephone number; otherwise we would have telephoned him

当然不一样


1句表示的意思是与过去事实相反的假设 与现在无关

而2句则是与现在事实相反的假设 意思是我现在身体不舒服的意思

你的问题用你的1句就可以回答了 用would（should）＋have＋V过去分词

一、 动词wish后宾语从句中的虚拟语气
1． 用wish表示现在的祝愿和报歉。
其句子结构为：宾语从句的谓语be和were(was)，实义动词用过去式。例：I wish the were at home this time.

2． 用wish表示对过去事情的遗憾。其句子结构为：宾语从句的谓语用过去完成时，或could+现在完成时。例：I wish I hadn' t hurt him so much。

3． 用wish表示对将来事情的愿望。其句子结构为宾语从句的谓语为would/could/might+动词原形。例：I wish I might be able to come tomorrow 。

二、 用在一般虚拟条件句中的虚拟语气
（一） 表示与现在、过去、将来事实相反的假设
1． 与现在事实相反的假设。
其句子结构为：
　　从句：if+主语+动词的过去式（be变were）+其他
主句：主语+would(should, could, might)+动词原形+其他
例：If I were you, I would go with him.
　2． 与过去事实相反的假设。
其句子结构为：
从句：If+主语+过去完成时+其他
主句：主语+should(would, could, might)+现在完成时+其他。例：If you had studied harder last term, you could have passed exam.
3．表示对将来事实实现的可能性不大的假设。
其句子结构为：
从句：If+主语+should (were to )+动词原形+其他
主句：主语+would (could, should, might)+动词原形
例：If he were to go tomorrow. He might tell you.

(二) 从句和主句要根据各自发所生的时间选用符合具体时间的虚拟语气形式
1． 从句表示过去，主句表示现在。
If they had stared the early morning yesterday, they would be here now.
2． 从句表示将来，主句表示过去。
If I were not to make a preparation for my experiment this afternoon, I would have gone to see the film with you last night。
3． 从句表示过去，主句表示将来。
If we hadn' t made adequate preparations, we shouldn' t dare to do the experiment next week。
4．从句表示将来，主句表示现在。
If we shouldn' t have an exam this afternoon. I would go
shopping now.

三、 可以引起与事实相反的方式状语从句，用虚拟语气 　　由as if、as though引起的与事实相反的句子，不论主句的谓语是现在时或者说过去时，其谓语表示的时间概念和句子结构，都基本上与wish后的宾语从句相同。例：
John pretends as if he didn' t know the thing at all, but in fact he knows it very well.(用过去式表示与现在事实相反的假设)
The old man looked at the picture, he felt as though he had gone back to time 20 years ago.（用过去完成式表示与过去相反的事实）
They talked and talked as if they would never meet again (would+动词原形，表示与将来事实相反)

四、在表示建议、命令、要求、忠告等动词的后面，其宾语从句的谓语用“should+动词原形”表示虚拟语气
常用的此类动词有：
表示“要求”的：ask, desire, request, demand, require, beg
表示“提议、劝告、建议”的：move, prpose, suggest, recommend, advise, vote
表尽熬龆ā⒚睢钡模篸ecide, order
表示“主张”的：maintain, urge
表示“同意、坚持”的：consent, insist
例：The doctor suggested that he (should) try to lose his weight.
He insisted that we (should ) tell him the news.
上述动词的名词形式，demand, desire, requirment, advice, order,decision, recommendation, suggestion, 以及necessity, preference, plan, motion, idea等名词，其后的表语从句或同位语从句，也用“should+动词原形“表示虚拟语气。现代英语，特别是美国英语，常省去“should”，例：
The advice is that we (should) leave at once.
He idea that we (should)visit Great Wall was warmly
welcomed.
　五、在“It is (was)+形容词（或过去分词）+that……”结构中，主语从句的谓语也用“should+原形动词“表虚拟语气

美国英语中省去should, 常用的形容词和过去分词有：
表示“要求”的：required, demanded, requested, desired, desirabl。
表示“建议”的：suggested, recommended,
表示“迫切、紧近、重要”的：imperative, urgent, necessary, essential, important, vital
表示“适当、较好”的：appropriate, advisable, better, preferable
表示“可能”的：probable, possible
表示“命令”的：ordered
例：It was necessary that we (should) make everything ready ahead of time.
It is required that nobody (should)smoke here.

六、由下列名词或短语引导，或含有某些词的从句中应用的虚拟语气
1．“Iest 以免、惟恐”引导的从句用“shuld+动词原形”。
He took a map with him lest he (should ) lose his wag there.
2．“whether不管、无论”引导的让步状语从句，有时用动词原形。
All things, whether you know or don' t know, exist in the world.
3．用“would rather/had rather' would just as soon"表示“宁愿、但愿”，后面的宾语从句谓语用过去式或动词原形表示对将来的要求，用过去时表示对现在的愿望，用过去完成时表示对过去做的事的懊悔。

Don' t live in the world, I would rather( I would just as
soon) you die.
I would rather you go tomorrow.
I would rather everything hadn' t happened in the past.
4．用“had hoped”表示原来希望做到而实际上未能实现的事情，其宾语从句的谓语用“would+动词原形”。
I had hoped that she would go to the U.S. and study there,
but she said she liked to stay in China.
5．在“It is（high/about）time+that”引导的定语从句中，定语从句的主谓语用一般过去时，偶尔也可以用would(或should)+动词原形，或had rather (would rather)+动词原形。
It is hihg (about)time that we left/should leave/ had better leave/had rather leave/ were leaving.(注意与“This is the first/second…time”后从句中用现在完成时的区别。
6．用“without/but for/in the absence of ”表示“要不是”，“如果没有”（相当于if it were not for…）表示条件时，句中一般用虚拟语气。（也可用陈述语气）
Without your help, I couldn' t finish my work on time.
In the absence of water and air, nothing could live
　7．由“providing (that)/ provided (that)/on condition that/ in order that”引导的条件从句或目的从句，根据情况，可用虚拟语气。（有时也可用陈述语气）
They are willing surrender provided they are given free
passage.
8．在if引导的虚拟条件句中，若有were, had, should, 在书面语中可省去if ,将were等提到主语前，形成倒装。
Should there be a good film tomorrow. I would go to the
theatre with you.
Were it not for your help. I wouldn' t be succeed.