虚拟语气
在英语文法中有三种语气，即直述式语气(Indicative Mood)、祈使语气 (Imperative Mood)和虚拟语气(Subjective Mood)，其中前两种我们早已熟悉了，这里则不多谈了，如： How beautiful she is! 则是直述式语气，而Hurry up! Don't hurry up 则是祈使语气。我们主要来看看虚拟语气的主要用法。虚拟语气主要是用来表达一种无法实现的愿望，一种与事实相反的情况，或者将不可能实现的，或可能性很小的事实，假想为事实予以表述。这样的动词结构称为虚拟语气。它主要有三种形式，即与现在事实相反的假设，与过去事实相反的假设，与将来事实相反的假设。它们具体结构如表８－７。
虚拟语气的构成
虚拟语气其他习惯用法简表
1 语法辨析
Incorrect: If I was a girl， I would marry you
Correct: If I were a girl， I would marry you
表示与现在事实相反的虚拟语气时，if条件句中的be动词一律用were，这句话应译为我要是个女孩，我就嫁给你。实际上不可能是个女孩。
Incorrect: If I were you I will not worry
Correct: If I were you I shouldn't worry
现在时的虚拟语气主句要用should 或would 加动词原形，这句话应译为我要是你的话，就没有必要烦恼。要注意这种语态用在这里实际上是想把要讲出的观点表达得婉转些，有礼貌些。
Incorrect: God forgives you!
Correct: God forgive you!
这里的主语 God 是第三人称单数，之所以动词不加 s 是因为要表达一种祝愿，即人力所不能及的事情，实际上是 forgive前有一助动词should， May 等，但在口语中将其省略了。如： May you be happy 祝你幸福。
Incorrect: If the weather was nice yesterday,
we would have gone to the zoo
Correct: If the weather had been nice yesterday， we would have gone to the zoo
因句中有 yesterday 一词即表示的是与过去相反的事实，即昨天天气很不好，我们也未去动物园，所以 if 条件句应用 had＋过去分词。
Incorrect: If it is was not snowing right now,I will go for a walk
Correct: If it was (were) not snowing right now， I would go for a walk
虚拟语态 be 动词作助动词时，则可用was来取代were， 如 was to。虚拟语态中的动词如果是表示正在进行之中也要用进行时态。
Incorrect: If you had taken my advice,
you would have been better now
Correct: If you had taken my advice,
you would be better now
这句话的意思是如果你以前要是能听我的忠告的话，你现在就会好多了。其条件句是与过去事实相反的虚拟句，而主句是与现在事实相反的虚拟句，这在语法书中叫做混合虚拟条件句。例如： If I had caught that plane， I would be dead now 即： The plane I intended to catch crashed and everyone was killed
Incorrect: He were you， he would go home at once
Correct: Were he you， he would go home at once
Correct: If he were you， he would go home at once
在虚拟条件句中的if可以省略，但if省略后其句子的结构要采用倒装语序。
Incorrect: Supposing your teacher saw you with me What does she think?
Correct: Supposing your teacher saw you with me， what might she think?
这句话中没有if条件句，但仍要用作虚拟语态。这里因为有些分词或介词短语，起到了从句的作用。这些短语有： without， providing, supposing， but for(you)…
Incorrect: To see the girl， you will like her
Correct: To see the girl， you would like her
这里的条件句是用不定式取代了。
Incorrect: I'm sorry I did have come here by car
Correct: I'm sorry I should have come here bycar
这里的条件句被省略了，其意为我真应该坐小车来。同样在句意不会混淆的情况下，主句也有时可以被省略，如：What if we should fail! (我们万一失败了如何)。 If he could do it, why not? (如果他能做，他怎么会不干呢?)
Incorrect: If the earth were (was) to turn from east to west， I will
give you this car as a gift
Correct: If the earth were(was) to turn from east to west I would give you this car as a gift
条件句中也常用were to 来表示说话者认为可能性极小或根本不可能的事。
Incorrect: If you'd have told him early， he would have passed the exam
Correct: If you had told him early， he would have passed the exam
非正式口语中往往听见外国人讲：'d have＋pp (过去分词)但仍没有人认为它是正确的句子，不易为我们效仿。
Incorrect: The little girl looked as if she would have seena ghost
Correct: The little girl looked as if she had seen a ghost
要注意的是 as if 从句中如果用虚拟语气，它的用法要与 if条件句的动词结构相同，即与现在事实相反动词用过去式，be 动词用were，而与过去事实相反的动词用had＋pp (过去分词)。另外更要注意的是，并非所有 as if 从句都要用虚拟语气。如： Itlooks as if it is going to snow (看天好像要下雪)即是真实条件句。
Incorrect: I should have come here early， but I had beenbusy
Correct: I should have come here early but I wasbusy
but 是转折连词，其后的句子是真实句，而不是虚拟句。
Incorrect: To tell the truth， I wish I know her address now
Correct: To tell the truth, I wish I knew heraddress now
wish的宾语从句中要用虚拟结构，与现在事实相反的条件动词要用过去式，be动词用were，与过去事实相反的条件动词要用had＋过去分词。如： I wished I had passed that exam
Incorrect: His homework was written badly
I wish he will do it better tomorrow
Correct: His homework was written badly
I wish he would do it better tomorrow
wish要用来表示对现状不满，希望将来有所改进，则要用would加动词原形。
并非wish不能表达真正的祝愿，但是不能接从句，而要用双宾语，或不定式，
如：I wish you luck (双宾语)
I wish you to be a good student
I wish to see her at once
Incorrect: I wish it will not be another failure
Correct: I hope it will not be another failure
Correct: I wish it would not be another failure
要注意 hope 与 wish 的不同用法。
2 例题解析
［例1］If he on tourists for his business， he would have to close his shop
A depends B will depend C depended Dhas depended
［答案］C． 这是与现在事实相反的假设。应译为：如果他仅靠旅游来做生意的话，他早就要关门了。
［例2］Had she been younger， she more beautiful
A had been B might have been C might be D would be
［答案］B． 因其条件句是省去if的与过去事实相反的假设。
［例3］If you that TV play last night， you wouldn't be sleepy
A haven't watched B didn't watch
C hadn't watched D wouldn't have watched
［答案］C． 因是与过去事实相反的假设。应译为：昨晚你要是不看那个电视剧，你现在也不会这么困倦了。这是混合虚拟句，主句是与现在事实相反的虚拟。
［例4］If it tomorrow， we will not go for the picnic
A will rain B had rained C rained D rains
［答案］D． 因其主句是将来时，所以条件句应用一般现在时表示将来。所以要注意的是有些真实条件句并没有虚拟的含意，不要乱用虚拟语态。
［例5］We had hoped that we go home at once
A did B will C / D would
［答案］D． had hoped 用来表达对过去未能实现的愿望，其宾语从句要用would加动词原形。
［例6］I want to see her today
I'd rather you
A didn't B do not C don't D do
［答案］A． 'd rather 其后如直接接动词则用动词原形。如加宾语从句则从句中谓语动词要用过去式。
［例7］It is very late， It's time
A we have left B we will leave
C we left D we leave
［答案］C． 要注意It is (high/about) time 其后可接 for something, 如：It is time for supper. 或 for somebody to do something 也可接从句，但从句中的谓语动词要用过去式，有时也可用should加动词原形，但should不可省略。
［例8］These typewritten papers are very neat
I wish I type too， but I don't know how
A can B may C could D will
［答案］C． 因wish在从句中表示与现在相反的虚拟，所以要用would或could。
［例9］It is important that he this work at once
A do B does C did D will do
［答案］A． 虚拟语气可以用来表示要求、建议、提议、命令、意愿等。在Itis ＋形容词(过去分词) ＋从句的结构中，从句中的谓语动词要用should加动词原形，其should在美语中经常省略。这样的形容词有： important， necessary， strange， natural。这样的过去分词有： demanded, requested, suggested， required， recommended。
［例10］The teacher ordered that the students her
A obeys B obeyed C obeying D obey
［答案］D． 因带有命令要求口气的动词其宾语从句中的谓语动词也要用should加动词原形。其should在美语中则被省略。这样的动词有：ask， advise， demand， desire， insist， order， recommend, require， request， suggest…
［例11］She rejected my suggestion that she her son the next week
A met B will meet C meet D would meet
［答案］C． 因同位语从句的谓语动词要用should加动词原形。这是因为其前面的名词是由［例10］中的那些表示愿望、命令、建议的动词转化而来的。
［例12］What's the matter with her?
I don't know but she looks she'd lost her boy friend
A that B so that C as D as if
［答案］D． 其意为她看上去好像是失掉了男朋友一样脸色不好看。
［例13］You finally passed the exam
Yes， your help. I would have not succeeded
A but that B but for C but if D thanks to
［答案］B． 由but for， without， supposing 等短语或连接词也可以引出虚拟语态。
［例14］ today， he would get there by the weekend
A Would he leave B Was he leaving
C Were he to leave D If he leaves
［答案］C． 如果条件句中if被省去，则要用倒装语序。be to在虚拟条件句中应用 were to 或 was to取代。
［例15］I wish I to talk this over with him when he was here last night
A was able B were able C had been able D should be able
［答案］C． 在wish从句中要表达对过去事实的一种不可能实现的愿望时，要用 had 加过去分词。
［例16］Jane appears as though she the secret
A knows B has known C is knowing D had known
［答案］D． 这是对过去事实的假设，as though ＝ as if
［例17］Her pale face suggested that she ill， and the teacher wanted to send her to the doctor's
A be B should be C were D was
［答案］D． 因 suggest 作建议讲时其宾语从句要用虚拟语气，但是作暗示则不要用虚拟语态。
［例18］Without electricity， human life quite different today
A is B be C will be D would be
［答案］D． 由 without 介词短语引出的虚拟条件句，其主句如表示与现在事实相反，则用should， would加动词原形。
［例19］He insisted that he do it alone
A wanted to B want to C should want to D wants to
［答案］A． 如果主句的主语与宾语从句的主语是同一个人时，insist从句中则不宜用虚拟语态。
［例20］If it so hard， we'd go home
A isn't raining B doesn't rain
C weren't raining D isn't going to rain
［答案］C．因is raining的过去时应为was raining，但在虚拟条件句中最好用were raining。