虚拟语气were 有哪些情况需要使用虚拟语气?

有哪些情况需要使用虚拟语气?  

有哪些情况需要使用虚拟语气?

虚拟语气表示说话人的主观愿望、猜疑、建议或与事实不符的假设等，而不表示客观存在的事实。虚拟语气是由句中的谓语从句的特殊形式表示出来的
在表示假想的虚假的、与事实相反的或难以实现的情况时用虚拟语气
即当一个人说话时欲强调其所说的话是基于自己的主观想法，愿望，假想，猜测，怀疑或建议，而不是根据客观实际，就用虚拟语气
非真实条件句表示的是假设或实际可能性不大的情况，故采用虚拟语气。
很复杂 最好买个语法书慢慢记

请教一下，虚拟语气有哪些情况？举出例子

语气（The Indicative Mood）直陈语气用于直截了当地陈述事实、描述状态：
He has published quite a number of essays this year .他今年已发表了好几篇论文。
2. 祈使语气（The Imperative Mood）
祈使语气用于提出请求、命令、建议或是劝告等：
Wait outside until you are asked . 请在外面等候，请你进再进去。
Let's just take a break, shall we ? 我们休息一会儿，好吗？
3. 虚拟语气（The Subjunctive Mood）
虚拟语气用于表示主观愿望和假设的虚拟情况。虚拟语气不太顾及事实的存在，它表现出说话人的主观因素比较多。所以说话人所讲的内容往往是与事实相反的；或是其实现的可能性微乎其微，甚至于没有实现的可能性。当然，有时为了使说话的语气客气、缓和、委婉，也使用虚拟语气。例如：
I wish you were more careful .但愿你更细心一些。
If I had more money, I would buy a bigger apartment.
我要是有再多一点钱，我就买一套更大一些房子。
Would you mind shutting the door ? 劳驾您把门关上。
一、虚拟语气在条件状语从句中的构成和用法
1. 表示一种与过去事实相反的假设情况，条件从句中的谓语动词要用“had+过去分词”，主句中的谓语动词要用“would / should / could / might+have+过去分词”。如： If you had e here yesterday, you would have seen him. 如果你昨天来到这里，你就会看见他了。 2. 表示一种与目前事实相反的假设情况，条件状语从句中的谓语动词要用一般过去式(be动词常用were)，而主句中的谓语动词则要用“would / should / could / might+动词原形”。如： If I had his telephone number, I would call him now. 如果我有他的电话号码，我现在就打电话给他。 If I were you, I would not tell him that. 如果我是你，我就不把那件事告诉他。 3. 表示与将来的事实可能相反的假设情况时，条件状语从句中的谓语动词要用：1) should+动词原形，或2) 一般过去式，或3) were+不定式，主句中的谓语动词要用“would+动词原形“。如： If it snowed tomorrow, many crops would die of cold. = If it were to snow tomorrow, many crops would die of cold. = If it should snow tomorrow, many crops would die of cold. 如果明天下雪，许多庄稼都会冻死。 4. 有时候，条件和结果不是指同一个时间，这时，应根据上面谈到的几种情况，使用相应的形式，这种虚拟语气形式被称为错综虚拟语气。如： If you had listened to the teacher carefully yesterday, you would know how to do the exercise now. 如果你昨天认真听了老师的讲话，你现在就知道如何做这道题了。 5. 使用虚拟语气时，有时候可以省略引导条件状语从句的连词if。这时，从句部分要使用部分倒装，即将从句部分的助动词were / had / should等提到主语前面。如： Were I you, I would not tell him that. Should it snow tomorrow, many crops would die of cold. Had you listened to the teacher carefully yesterday, you would know how to do the exercise now. 二、含蓄性条件句
在表示假设的虚拟语气中，有时假设的条件并不以条件从句的形式出现，而是通过上下文或句中内在的逻辑关系，或用其它形式表达出来，这就是“含蓄条件句”。常用的有以下四种： 1. 介词短语常用来表示虚拟条件的介词有without, with, in, under, but for等，他们表示的虚拟条件都可以被if从句替换。 1) without, with without表示否定的条件，意为if…not；with与without意义相反，表示肯定的条件。如： Without air (= If there were no air) , there would be no living things. 如果没有空气，就不会有生物。 With his help (= If I had her help), I would do the experiment well. 如果有他的帮助，我会做好这个实验。 2) under 如： Under the leadership of a less experienced person (= If there had been the leadership of a less experienced person), the experiment would have failed. 要是一个没有经验的人领导，这个实验就失败了。 3) in 如： I would have lost my head in that position (in that position = if I had been in that position) 我处在那种情况下，是会丧失理智的。 4) but for (如果没有) 如： But for their help (= If it were not for their help), we could not get over the difficulties. 要不是他们的帮助，我们是克服不了这些困难的。 2. 连接词or / otherwise (否则，要不然), but, but that (要不是) 如： He felt very tired yesterday, or he would have attended the party. 他昨天很累，不然他就参加那个聚会了。 He was having a meeting, otherwise he would have e over to help us. 他当时正在开会，否则他就会来帮助我们了。 I should have returned the book last week, but I was so busy that I fot to do so. 我本来应该在上周归还那本书的，但我太忙了，把这件事给忘了。 But that you had seen me in the water, I would have drowned. 要不是你看见我掉在水里，我早就被淹死了。 3. 分词短语 如： United (= If they had been united), they wouldn’t have been defeated. 他们要是团结起来，就不会被打败。 Seen from a high mountain (= If it were seen from a high mountain), the field in which wheat is growing would look like a great green sea. 倘若从高山上看，麦田就像一片碧绿的大海。 4.“名词+and”结构 如： One step further and you would be dead. (= If you took one step further, you would be dead.) 再往前走一步，你就会死。 三、虚拟语气在名词性从句中的应用
虚拟语气有时可用于主语从句、宾语从句、表语从句和同位语从句中，下面分别加以说明。 1. 主语从句
在主语从句中用以表示惊奇、惋惜、理应如此等意，其谓语用should +动词原形，should 在口语中可省略。主要用于以下三种结构： 1)Itis necessary/important/natural / strange/essential /advisable/desirable/urgent …+that... 如： It is necessary that he (should) get everything ready by tomorrow evening. 到明天晚上前把一切准备好是必要的。 It is important that you (should ) read English aloud every morning. 你们每天早上朗读英语很重要。 2) It is a pity (a shame, no wonder...)+that... 如： It is a pity that she (should )be so careless. 她这么粗心真是遗憾。 It is no wonder that they (should) go there by air. 难怪他们要坐飞机到那里去。 3) It is suggested( decided, ordered, requested, desired, demanded, required, proposed, remended) that ...如： It is requested that that factory (should) s polluting the river. 要求那家工厂停止对那条河的污染。 It is decided that the sports meet (should) be put off till next week. 已决定运动会推迟到下星期。 2. 宾语从句
1) 在表示命令、建议、劝告、欲望、要求、主张这一类动词后的宾语从句中，从句应用虚拟语气，其谓语用should+动词原形，should可省略，这类动词有suggest, insist, demand, request, desire, order, ask, advise, propose , mand, remend, require等，如： The teacher insisted that we (should) use an English-English dictionary. 老师坚持要我们使用英英词典。 I suggest the invitation to the conference (should) be sent to Dr Baker. 我建议给贝克博士发出出席的邀请。 2) wish 后的宾语从句要用虚拟语气，表示不能实现的愿望。表示现在不能实现的愿望，从句谓语动词用过去式；表示将来不能实现的愿望，从句谓语动词用could/would+动词原形；表示过去不能实现的愿望，从句谓语用“had+过去分词”。如： I wish I were a bird. 我要是一只鸟多好啊！ I wish I had started to study English years ago. 我要是早几年开始学英语就好了。 I wish you would s asking silly questions. 但愿你不要再问愚蠢的问题了。 3) would rather“宁愿，宁可”后接从句，从句用过去时指现在或将来；用过去完成时指过去，如： I'd rather you went there now. 我宁愿你现在就去那里。 I would rather he came to see me tomorrow. 我宁愿他明天来看我。 I would rather he hadn't told you about it. 我宁愿他没有把这件事告诉你。 4) Would you mind if ... ? 这是表示请求许可的句型，if 从句用虚拟语气，谓语用一般过去时，如： Would you mind if I smoked in the next room ? 我在隔壁房间里抽烟你介意吗？ 3. 表语从句
1) as if /though（似乎，好像，仿佛）引导的表语从句如果表示与现在事实相反，谓语动词用一般过去时；表示与过去事实相反，谓语动词用过去完成时；表示与将来事实，谓语用would /might/ could+动词原形。如： It is so cold that it seems as if we were in Siberia. 天真冷好像我们到了西伯利亚似的。 It looks as if it might rain. 看起来好像要下雨。 2) 当表示间接的要求、建议、命令、决定、欲望、劝告、主张等名词作主语时，其表语从句用虚拟语气。这类名词有suggestion, proposal , request, order, advice, idea, demand, remendation等，其谓语用(should)＋动词原形。如： Our suggestion is that you (should) be the first to go. 我们的建议是你应该先去。 My idea is that he (should) do his homework first. 我的想法是他先做作业。 4. 上述名词的同位语从句也用虚拟语气，其谓语用(should)＋动词原形。如： Do you know the order that you (should ) keep watch ? 你知道你该去放哨的命令吗？ We all agreed to his suggestion that we (should ) go to Beijing for sightseeing. 我们都同意他要我们去北京浏览的建议。 四、虚拟语气在定语从句中的运用
在“It is (high) time (that)…”句型中(that)引导的是定语从句，从句的谓语动词习惯上用过去式，(有时也可用should+动词原形，should不能省略)，表示“早该干某事了，是某人该干某事的时候了”。如： It is time we went (should go) home. 我们该回家了。 It’s high time you made (should make) up your mind. 是你下决心的时候了。 五、虚拟语气在状语从句中的运用
1. 在in order that, so that引导的目的状语从句中，用may或might+动词原形(so that从句中也可用can或could)表示虚拟语气。如： If you do know, answer in a loud enough voice in order that (so that) all the class may hear. 如果你真的知道，你就大声回答，以便让全班同学都能听到。 He came ten minutes earlier in order (so that) he might get a good seat. 为了搞到个好坐位，他早十分钟来了。 2. asif/ though（似乎，仿佛）引出的方式状语从，如果表示真实情况应该用直陈语气；
如果表示非真实情况则应该用虚拟语气, 其谓语动词的虚拟式与wish后面宾语从句中谓语动词的虚拟式相同。 1) 与现在事实相反，用动词过去式，be动词用were。如：
He talks as if he knew everything in the world. 他谈起话来好像他知道世间的一切似的。 He speaks English as if he were an Englishman. 他说起英语来就好像他是个英国人似的。 2) 与过去事实相反，用“had+过去分词”的虚拟结构。如： He behaved as if nothing had happened. 他表现出好像什么都没发生似的。 He talks as if he had been to the moon. 他谈起话来好像他上过月球似的。 3) 与将来事实相反，用“would (might)+动词原形”的虚拟结构。如： She cried as if her heart would break. 他哭得心都要碎了。 六、if only引导的句中虚拟语气的用法
“If only…从句 “表示一种愿望或是向往的假设，其意义是"要是……就好了”、 “但愿……”。这个句型中的语序是正常语序，不倒装。另外，其谓语动词的虚拟式与wish后面宾语从句中谓语动词的虚拟式相同。例如：
If only she could understand my real feelings.
要是她能了解我的真实想法就好了。
If only my mother had survived the disease and lived till now.
要是我妈妈没有死于疾病而活到现在就好了。
If only he would fine a satisfactory job after his graduation.
但愿他毕业后找到一份称心如意的工作。 七、“情态动词+have done”的虚拟结构
1. 在对过去应该做而没做的事情表示责备的句子中，谓语用“should+have done”的虚拟结构。如： You should have been here five minutes ago. 你本应该5分钟前就到这儿。 I should have told you about it earlier. 有关这事我本应该早告诉你。 2. “could+have done”虚拟语气，表示对过去事情的假设，意思是本来能够做某事而没有做。如： He could have passed the exam, but he was too careless. 本来他能够通过考试，但是他太粗心。 “There were already five people in the car, but they managed to take me as well.” “It couldn’t have been a fortable journey.” “车里已经有五个人了，他们又设法带上了我。” “那一定不会是个舒服的旅程。” 3．“might+have done”可表示虚拟，意思是过去某个动作有可能发生，但实际上并没发生。 He might have given you more help, even though he was busy. 他或许会多给你一些帮助，即使他很忙。 She might have achieved greater progress, if you had given her more chances. 如果你多给她点机会，她可能已经取得了更大的成绩。 4．“would+have done”虚拟语气，表示对过去事情的假设，意思是“本来会做”。如： I would have told you all about the boy’s story, but you didn’t ask me. 我本来会告诉你这个小男孩的故事，但是你没有问我。 Without your help, I wouldn’t have achieved so much. 没有你的帮助，我是不会取得如此大的成绩的。 5．“should+have done”虚拟语气，含有指责对方或自责的意思，意为“本来应该做某事，而实际没做”。其否定式表示本不应该做某事而实际上做了。如： Tom, you are too lazy. The work should have been finished yesterday. 汤姆，你太懒惰了，这个活本来应该昨天就做完的。 Look, Tom is crying. I shouldn’t have been so hard on him. 看，汤姆哭了，我本来不应该对他如此严厉。 6．“ought to+have done”表示过去应该做而实际没有做，意为“理应做……”，往往表示遗憾。其否定式表示过去本不应该做某事而实际上做了。如： You ought to have gone home last Sunday. 我理应上星期天回家的。 You ought to have given him more help. 你理应多帮助他 7．“need+have done”表示本来需要做某事而没有做，其否定式为本不必做某事而实际上做了。如： I needn’t have bought so much wine—only five people came. 我本来没必要买这么多酒，只来了五个人。 He need have hurried to the station. In that case, he wouldn’t have missed the train. 他本来需要快点去车站，那样的话，他就不会误了火车。 8. “ would rather+ have done” 表示宁愿过去干了某事，而实际上并没发生；其否定形式意思为表示宁愿过去没干某事，而实际上却做了。 I raised objections at the meeting. I’d rather haven’t. 我在会上提了反对意见， 我倒愿没有这样。 八．虚拟语气用于口语交际场合
虚拟语气常用于表示客气、委婉的说法。它之所以能表示客气、委婉的意思，就是因为它的语气是虚拟的；也就是说，讲话的人有意识地将其所说的内容虚拟化，从而给听话人在是否接受所听到的内容方面留有较大空间、余地；而不至于使听话人在是否接受所听到的内容方面感到有压力或是强迫感。从这个意义上讲，虚拟语气比直陈语气，祈使语气更为客气、委婉、礼貌。例如：
Could you tell me the way to the nearest shopping center ?
你能告诉我去最近的购物中心的路吗？
Would you mind lowering your voice? 请你小声点儿，行吗？
Perhaps you could get better results this way .你这样做效果或许要好一点。
Which seat might I take? 我可以坐哪个位子？
九．一些动词的过去完成时表虚拟
在英语中一些表示“希望，打算，计划，意图”的动词, 如：hope, plan, want, think, expect, mean, intend, wish, 等的过去完成时，可表示未能实现的打算，计划，愿望等。 I had planned to visit you, but I had an unexpected visitor. The firefighters had wished to put out the fire in one hour, but they failed. 十．不定式结构中的虚拟语气现象
would/should like to have done, 动词“hope, plan, expect, mean, intend, wish”的过去式+ to have done 以及 was/ were to have done 也可表示虚拟。表示本打算，计划干某事，但事实上并未发生。be supposed to have done 相当于should have done The plane was to have taken off at 8 o’clock, but it was held up because of a heavy fog. I hoped to have pleted the work before now. You are supposed to have pleted the work by now.

wish的虚拟语气考点有哪些

1)用于wish后面的从句，表示与事实相反的情况，或表示将来不太可能实现的愿望。其宾语从句的动词形式为：
真实状况 wish后
从句动作先于主句动词动作 现在时 过去时
(be的过去式为 were)
从句动作与主句动作同时发生 过去时 过去完成时
(had + 过去分词)
将来不大可能实现的愿望 将来时 would/could +
动词原形
I wish I were as tall as you. 我希望和你一样高。
He wished he hadn't said that. 他希望他没讲那样的话。
I wish it would rain tomorrow. 我希望明天下雨就好了。
2)Wish to do表达法。
Wish sb / sth to do
I wish to see the manager. = I want to see the manager.
I wish the manager to be informed at once. (= I want the manager to be informed at once.)

insist 的用法有哪些？在哪些情况下要用虚拟语气，哪些不用呢？

insist
1、意思是“坚持要”表示命令、要求，其后之宾语从句要用虚拟式动词原形
或者“should + 动词原形”
例句：
I insist that you (should) be present.
They insisted that she (should) be invited.
I insist that you (should) see a doctor.
She insisted that he (should) go.
这种虚拟语气的用法除了“insist”还有：demand,suggest,order,propose.
2、意思是“坚持说，硬说”，其后宾语从句用普通时式，不用虚拟语气的哦。
例句：
She insisted that he was wrong.
虚拟语气知识 详见::examwin./xuni.htm

虚拟语气应该怎么使用啊？有哪些原则？

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, remend, 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.

什么情况下要用虚拟语气

A:
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 e 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 beeen 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 e 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.

如果他不听取我的建议，他就不会干得这样好。

怎样区分insist做虚拟语气还是不做虚拟语气的情况呢

"insist"
一.
当"insist" 表示“坚持说；坚决认为”，接that从句，用陈述语气.(从句常为系表结构或从句谓语动作发生于主句谓语动作之前）即是陈述已知或发生过的事.
例:
(1)She insisted that he was wrong.
她坚持认为他错了
(2)He insisted that he had done right.
他坚决认为自己做对了
二.
当"insist" 表示“坚决主张；坚持要求”，接that从句，用虚拟语气。即“should＋动词原形”，should可省略。表示对将来事实"可能相反"的一种虚拟.
一般考试多考的是insist接虚拟语气的用法,
区别主要还是在于"insist"在句中所表达的意思.

suggest that什么情况下不用虚拟语气

suggest 后面加从句时，一般可以有两个意思：

提议，建议

表明，意思是

当suggest在句子中是第二个意思时，不用虚拟式。

in case虚拟或非虚拟语气的情况的区别

1. in case 的意思可以理解为“在...的条件/前提下”，是否要使用虚拟语气，要看说话人提出的条件是真是假。如果条件是已经发生过的与事实相同，或者在将来发生的可能性大，我们认为就是“真的”，不用虚拟语气。如果提出的条件是与已经发生的事实相反，或者在将来基本不可能发生，我们认为是“假的”，就要使用虚拟语气了。上下文应该会有语境提示，用来分辨真假，或者通过主从句的配合也可以判断。
2. 如果不用虚拟语气，那么就等同于一般的条件句，现在时和将来时形式是一样的，主句 will do（将来时），从句 do(一般时)，（也就是常说的主将从现） 过去时态的句子：主句 would /should / could / might + do （过去将来时），从句 did (过去时)
3. 使用虚拟语气的规则和IF虚拟（非真实）条件句是一样的，要倒退一格时态，也就是：现在时和将来时形式是一样的，主句would do（过去将来时），从句 did(一般过去时)，过去时态的句子：主句 would /should / could / might +have done，从句 had done (过去完成时)
总结一句话，in case 的用法和if 是一样一样的！不懂的话hi我

if only后面用虚拟语气 一共有几种情况？

与现在事实相反的用一般过去式。例如：If only he could e here now!
与过去事实相反的用过去完成时。例如：If only I had finished my homework yesterday!