一、考查虛擬語氣在條件從句中的用法
虛擬語氣在條件從句中的用法是其最基本的用法，也是高考最可能涉題的用法。為了便于理解和記憶，我們虛擬語氣在虛擬條件從中的用法分為三類--涉及現(xiàn)在時(shí)間的虛擬條件，涉及過去時(shí)間的虛擬條件，涉及將來時(shí)間的虛擬條件。下面就是這三類基本句型的謂語動(dòng)詞形式：
時(shí)間 從句謂語形式 主句謂語形式
將來 一般過去時(shí)(be用were) would/should/might/could+動(dòng)詞原形
現(xiàn)在 一般過去時(shí)(be用were) would/should/might/could+動(dòng)詞原形
過去 過去完成時(shí) would/should/might/could have+過去分詞
【有關(guān)考題】（答案分別為CBD）
(1) If he _______ my advice, he wouldn’t have lost his job. (2010湖南卷)
A. followed B. should follow C. had followed D. would follow
(1) If we _______ the other road, we might have arrived here in time for the meeting. (2010陜西卷)
A. taken B. had taken C. took D. have taken
(1) -John went to the hospital alone.
-If he _______ me about it, I would have gone with him. (2010天津卷)
A. should tell B. tells C. told D. had told
二、考查特殊句型中的虛擬語氣
英語中需要使用虛擬語氣的特殊句型不多，主要有以下類：
1. “倒裝”類虛擬語氣
當(dāng)虛擬條件句中含有were, should, had時(shí)，有時(shí)可將引導(dǎo)虛擬條件句的連詞if省略，而將從句中的were, should, had 提到句首，構(gòu)成倒裝形式的虛擬語氣。如：
If he were here, she would agree too. →Were she here, she would agree too. 如果她在這里，她也同意的。
If it should rain tomorrow, we should have to put off the match. →Should it rain tomorrow, we should have to put off the match. 假若明天下雨，我們只好推遲這場比賽。
If we had found him earlier we could have saved his life.→Had we found him earlier we could have saved his life. 要是我們當(dāng)時(shí)早點(diǎn)找到他的話，我們就可以救活他。
注意，如果條件從句的謂語為否定式，其中的否定詞not應(yīng)置于主語之后，而不能與were, should, had 等縮略成Weren’t, Shouldn’t, Hadn’t而置于句首。如：我如不是警告了你，你就可能喪命了。
正：If I hadn’t warned you, you could have been killed. 正：Had I not warned you, you could have been killed.
誤：Hadn’t I warned you, you could have been killed. 另外，有時(shí)省略if后提前到句首的had可能不是助動(dòng)詞，而是實(shí)義動(dòng)詞。如：Had I time, I would go with you. 假如我有時(shí)間，我就同你們一起去。句中的had不是構(gòu)成過去完成時(shí)的助動(dòng)詞，而是表示“有”，如果不省略if，其完整形式為：If I had time, I would go with you.
【有關(guān)考題】（答案分別為AB）
(1) Had I known about this computer program, a huge amount of time and energy _______. (2010浙江卷)
A. would have been saved B. had been saved C. will be saved D. was saved
(1) _______ fired, your health care and other benefits will not be immediately cut off. (2006湖北卷)
A. Would you be B. Should you be C. Could you be D. Might you be
3. “寧愿”類虛擬語氣
這里說的“寧愿”主要是指would rather。當(dāng)它后接句子的時(shí)候，句子的謂語通常要用虛擬語氣，其用法及結(jié)構(gòu)形式為：若從句內(nèi)容是涉及的是對現(xiàn)在或?qū)砬闆r的希望，則從句謂語用一般過去時(shí)；若從句內(nèi)容是涉及的是對過去已發(fā)生情況表示遺憾或后悔，則從句謂語用過去完成時(shí)。如：
I’d rather you went home now. 我希望你現(xiàn)在就回家。
Tomorrow’s difficult. I’d rather yon came next weekend. 明天有困難，我希望你下周末來。
I’d rather I had gone to the theatre last night. 我倒希望我昨晚我去了劇院看戲。(zn)
【有關(guān)考題】（答案為B）
George is going to talk about the geography of his country, but I’d rather he _______ more on its culture. (2010江蘇卷)
A. focus B. focused C. would focus D. had focused
4. “建議”類虛擬語氣
但是，若suggest表示“暗示”“表明”“指出”“提出(看法)”等，則從句謂語要用陳述語氣。如：
His smile suggested that he was satisfied. 他的微笑表明他是滿意的。
【有關(guān)考題】（答案為A）
Teachers recommend parents _______ their children under 12 to ride bicycles to school for safety. (2010福建卷)
A. not allow B. do not allow C. mustn’t allow D. couldn’t allow
【有關(guān)考題】（答案為C）
The workers will go on strike if the demands they _______ put forward are turned down. (2006福建卷)
A. could B. would C. 不填 D. had
答案為C。
7. “堅(jiān)持”類虛擬語氣
這類虛擬語氣主要指動(dòng)詞insist后接賓語從句時(shí)所用的虛擬語氣--若從句內(nèi)容是既成的事實(shí)，不容置疑，則從句謂語用陳述語氣，此時(shí)insist的意思是“堅(jiān)持說”；若從句內(nèi)容雖然還不是事實(shí)，但非常希望它成為事實(shí)，從句謂語用虛擬語氣，即采用“should+動(dòng)詞原形”的形式，且其中的should在美國英語中可以省略，此時(shí)insist的意思是“堅(jiān)持要”。比較并體會(huì)：
He insisted that I had read his letter. 他堅(jiān)持說我看過他的信。
He insisted that I should read his letter. 他堅(jiān)持要我看他的信。
He insisted that he was not ill, but the doctor insisted that he should take the medicine. 他堅(jiān)持說他沒有病，但醫(yī)生卻堅(jiān)持要他服藥。
8. “愿望”類虛擬語氣
這類虛擬語氣主要指動(dòng)詞wish和固定搭配if only后所接從句使用的虛擬語氣，但不包括動(dòng)詞hope在內(nèi)。此類虛擬語氣的結(jié)構(gòu)特點(diǎn)如下：
從句所涉及時(shí)間 從句謂語形式
從句內(nèi)容涉及現(xiàn)在情況 一般過去時(shí) / 過去進(jìn)行式
從句內(nèi)容涉及過去情況 過去完成時(shí) / would (could)+have +過去分詞
從句內(nèi)容涉及將來情況 would (could, might)＋動(dòng)詞原形
I wish I could swim. 我要是會(huì)游泳就好了。
I wish I had been here yesterday. 我真希望我昨天在這里。
I wish he could come tomorrow. 我希望他明天能來。
I wish you would come if you had time. 你如有時(shí)間的話，我希望你來。
If only I knew her name! 我要是知道她的名字就好了!
If only you had let me know earlier. 要是你早點(diǎn)讓我知道就好了。
If only she would go with me! 她要是愿意和我一道去就好了!
9. “似乎”類虛擬語氣
這類虛擬語氣主要指由表示“好像”和“似乎”的as if以及as though引出的虛擬語氣句子。既然是“好像”怎么樣，或者是“似乎”怎么樣，所以它描述的內(nèi)容就不大可能是事實(shí)，或者說可能是非真實(shí)的，所以它的謂語通常要用虛擬語氣，其結(jié)構(gòu)形式與wish后從句的謂語形式差不多。如：
I’ve loved you as if you were my son. 我愛你就像我的兒子。
He talks as if he had a potato in his mouth. 他講起話來仿佛嘴里含了一個(gè)土豆似的。
She looked as if she had seen a ghost. 她看起來好像剛才遇見了鬼似的。
根據(jù)各句的句意可知，“你”顯然不是“我”的兒子，所以第一句中as if從句的內(nèi)容是非真實(shí)的，故用虛擬語氣；“他”說話的時(shí)候嘴里肯定沒有含一個(gè)土豆，所以第二句中as if從句的內(nèi)容也是非真實(shí)的，故也用虛擬語氣；大家知道“鬼”是不存在的，所以她好像見到鬼的內(nèi)容也是不真實(shí)的，所以第三句的as if從句也用虛擬語氣。
但是，如果說話者認(rèn)為as if或as though從句所表示的內(nèi)容是真實(shí)的，或者說是有可能成為事實(shí)的，那么也可以使用陳述語氣。如：
We’ve missed the bus. It looks as if we’ll have to walk. 我們錯(cuò)過了公共汽車，看來我們得走路了。
10. “時(shí)候”類虛擬語氣
這類虛擬語氣主要是指It’s time…（是做某事的時(shí)候了）后接從句時(shí)所使用的謂語形式--不管是針對現(xiàn)在還是將來的情況，一律使用一般過去時(shí)。如：
It’s time we ordered dinner. 現(xiàn)在該叫菜了。
It’s time you washed those trousers. 你該洗洗那條褲子了。
I’m getting tired. It’s time we went home. 我累了，我們該回家了。
另外，有時(shí)還可在名詞time前加上修飾語high表示強(qiáng)調(diào)。如：
It’s high time you bought a new car. 你早該買輛新車了。
有一點(diǎn)值得注意，就是動(dòng)詞be在這類虛擬語氣中的用法與其他的虛擬語氣結(jié)構(gòu)不同，前面我們講到動(dòng)詞be在虛擬語氣句式中通常在該用was的時(shí)候而用were，但是it’s time后的從句中，該用was的時(shí)候不能用were來代替。如：
大家都該上床睡覺了。
誤：It’s time everyone were in bed. 正：It’s time everyone was in bed.
11. “若不是”類虛擬語氣
英語中有三個(gè)表示“若不是”“要不是”的固定表達(dá)，它們總是用于引出虛擬條件，句子謂語總是用虛擬語氣。這三個(gè)固定表達(dá)是but for, if it were not for, if it had not been for。如：
The car broke down. But for that we would have been in time. 汽車出毛病了。要不是那個(gè)我們會(huì)及時(shí)趕到的。
If it weren’t for your help, I would still be homeless. 若非你的幫助，我仍會(huì)無家可歸。
If it hadn’t been for the doctor’s care, I wouldn’t have recovered so soon. 要不是醫(yī)生的照顧，我不會(huì)痊愈得這么快。注：介詞without有時(shí)也可表示虛擬條件，意為“若不是”“要不是”，與but for用法相同。如：
Without [=But for] your help, I would have failed. 要不是有你的幫助，我就會(huì)失敗了。
但是，without也可以不表示條件，只表示“沒有”的意思。如：
Without a word he left the room. 沒有說一句話他離開了房間。
【有關(guān)考題】（答案分別為BD）
(1) But for the help of my English teacher, I ________ the first prize in the English Writing Competition. (2009福建卷)
A. would not win B. would not have wonC. would win D. would have won
(2) But for their help, we ________ the program in time. (2009安徽卷)
A. can not finish B. will not finish
C. had not finished D. could not have finished