虛擬語氣是一項語法難點，為了讓學員們便于理解與記憶，我們把虛擬語氣分成三大塊來討論：1．名詞從句中的虛擬語氣 標志詞+should+動詞原形2．條件從句中的虛擬語氣 ①三種基本態(tài) ②倒裝虛擬句 ③混時虛擬句 ④含蓄虛擬句 ⑤跳層虛擬句3．其它情形中的虛擬語氣（wish/would rather/It’s high time…/If only…/lest）
一．三種基本形態(tài)（1）
表虛擬的時間 if從句謂語形式 主句謂語形式
現(xiàn)在： did / were would (should, might, could)+do
過去： had done/ had been would (should/might/could)+have done(been)
將來： were to/ should+do would (should, might, could)+do
三種基本形態(tài)（2）（這是基礎，建議牢記下面的例句，爭取能脫口而出）
與現(xiàn)在事實相反：If I had enough money, I would buy a book.
與過去事實相反：If I had had enough money, I would have bought a book.
與將來事實相反：If I were to have enough money, I would buy a book.
If I should have enough money, I would buy a book.
二、倒裝虛擬句（只能與過去/將來事實相反，省去if，只有三種倒裝形式）
Had I had enough money, I would have bought a book.
Were I to have enough money, I would buy a book.
Should I have enough money, I would buy a book.
三、混合時間虛擬語氣（主要是抓住時間狀語）
(對過去事實虛擬+對現(xiàn)在事實虛擬)
If I had studied English at school, I could read the English novel now.
(對現(xiàn)在事實虛擬+對過去事實虛擬)
If she were not so careless, she wouldn’t have made such a mistake.
四、含蓄虛擬句（在四級考試中目前還未出現(xiàn)此考點，但在閱讀中常見）
What would I have done without you?
But for their help, I would not have finished the task.
But that the doctor arrived on time that day, they would have been dead.
Given more time, I would have been able to finish the test.
五、跳層虛擬句（即句子一半為虛擬，另一半為陳述語氣；but前句用虛擬而or/otherwise后句用虛擬） (but) He would put on weight, but he doesn't eat much. (與現(xiàn)在事實相反)
He would have put on weight, but he didn't eat much. (與過去事實相反)
(or, or else, otherwise) I forget where I read the article, or I would show it to you now. (與現(xiàn)在相
Mary couldn't have received my letter, otherwise she would have replied before now. (與過去相
六、名詞從句虛擬語氣(1) ask, advise, beg, command, demand, decide, desire, insist, order, prefer, propose, require, recommend, request, suggest, urge等表示命令、要求、建議等含義的動詞后的賓語從句中，謂語動詞用(should)+動詞原形, eg. I suggest / suggested that we (should) go tomorrow.名詞從句虛擬語氣(2) It is +(形容詞/過去分詞/特定名詞)+that的從句中，形容詞主要是表示令人吃驚的、重要的、必要的、關鍵的等詞匯。形容詞：astonishing, amazing, advisable, appropriate, crucial, desirable, essential, important, imperative, keen, necessary, natural, normal, odd, proper, preferable, strange, sorry, shocked, surprising, urgent, unusual, vital等。名詞從句虛擬語氣(3) 過去分詞：decided, desired, demanded, ordered, requested, recommended, suggested等;名詞：advice, decision, desire, demand, suggestion, motion, pray, resolution, wish, preference, proposal, recommendation, requirement, idea, order等
七、其它虛擬語氣 Wish…
I wish I knew the answer.(與現(xiàn)在事實相反)/ I wish I had known the answer. (與過去事實相反)
I wish you would shut up. (與將來事實相反)
If only… If only I were taller. (與現(xiàn)在事實相反)/ If only he had followed your advice! (與過去事實相反) /If only the rain would stop. (與將來事實相反)
It is (high/about) time… It is time you thought about your future.
would rather… I would rather you didn’t speak rudely to her. (與現(xiàn)在事實相反)
I’d rather you hadn’t spoken rudely to her. (與過去事實相反)
Lest…, in case…, for fear that…（引導的是目的狀語從句，但可歸入第六點(名詞從句虛擬)，這是因它們答案特征相同，即 (should)+動詞原形。eg. He took his umbrella lest it should rain.
大學英語虛擬語氣考題總結:答案的特征
1.(should)+動詞原形(一般式/被動式/否定式)記住信號詞（名詞，動詞，形容詞，分詞等）以及l(fā)est.2. 一般過去時：wish/If only…/would rather/It’s time (high/about) that….
3.基本形式（主要考與過去和將來相反的虛擬語氣）,特別注意時間狀語(混合時間虛擬)
4.倒裝的兩個時間：與過去，與將來相反；三個形式(Had/Were/Should)提前大寫，if省去；
5.but/or/or else/otherwise(跳層虛擬語氣)
一．三種基本形態(tài)（1）
表虛擬的時間 if從句謂語形式 主句謂語形式
現(xiàn)在： did / were would (should, might, could)+do
過去： had done/ had been would (should/might/could)+have done(been)
將來： were to/ should+do would (should, might, could)+do
三種基本形態(tài)（2）（這是基礎，建議牢記下面的例句，爭取能脫口而出）
與現(xiàn)在事實相反：If I had enough money, I would buy a book.
與過去事實相反：If I had had enough money, I would have bought a book.
與將來事實相反：If I were to have enough money, I would buy a book.
If I should have enough money, I would buy a book.
二、倒裝虛擬句（只能與過去/將來事實相反，省去if，只有三種倒裝形式）
Had I had enough money, I would have bought a book.
Were I to have enough money, I would buy a book.
Should I have enough money, I would buy a book.
三、混合時間虛擬語氣（主要是抓住時間狀語）
(對過去事實虛擬+對現(xiàn)在事實虛擬)
If I had studied English at school, I could read the English novel now.
(對現(xiàn)在事實虛擬+對過去事實虛擬)
If she were not so careless, she wouldn’t have made such a mistake.
四、含蓄虛擬句（在四級考試中目前還未出現(xiàn)此考點，但在閱讀中常見）
What would I have done without you?
But for their help, I would not have finished the task.
But that the doctor arrived on time that day, they would have been dead.
Given more time, I would have been able to finish the test.
五、跳層虛擬句（即句子一半為虛擬，另一半為陳述語氣；but前句用虛擬而or/otherwise后句用虛擬） (but) He would put on weight, but he doesn't eat much. (與現(xiàn)在事實相反)
He would have put on weight, but he didn't eat much. (與過去事實相反)
(or, or else, otherwise) I forget where I read the article, or I would show it to you now. (與現(xiàn)在相
Mary couldn't have received my letter, otherwise she would have replied before now. (與過去相
六、名詞從句虛擬語氣(1) ask, advise, beg, command, demand, decide, desire, insist, order, prefer, propose, require, recommend, request, suggest, urge等表示命令、要求、建議等含義的動詞后的賓語從句中，謂語動詞用(should)+動詞原形, eg. I suggest / suggested that we (should) go tomorrow.名詞從句虛擬語氣(2) It is +(形容詞/過去分詞/特定名詞)+that的從句中，形容詞主要是表示令人吃驚的、重要的、必要的、關鍵的等詞匯。形容詞：astonishing, amazing, advisable, appropriate, crucial, desirable, essential, important, imperative, keen, necessary, natural, normal, odd, proper, preferable, strange, sorry, shocked, surprising, urgent, unusual, vital等。名詞從句虛擬語氣(3) 過去分詞：decided, desired, demanded, ordered, requested, recommended, suggested等;名詞：advice, decision, desire, demand, suggestion, motion, pray, resolution, wish, preference, proposal, recommendation, requirement, idea, order等
七、其它虛擬語氣 Wish…
I wish I knew the answer.(與現(xiàn)在事實相反)/ I wish I had known the answer. (與過去事實相反)
I wish you would shut up. (與將來事實相反)
If only… If only I were taller. (與現(xiàn)在事實相反)/ If only he had followed your advice! (與過去事實相反) /If only the rain would stop. (與將來事實相反)
It is (high/about) time… It is time you thought about your future.
would rather… I would rather you didn’t speak rudely to her. (與現(xiàn)在事實相反)
I’d rather you hadn’t spoken rudely to her. (與過去事實相反)
Lest…, in case…, for fear that…（引導的是目的狀語從句，但可歸入第六點(名詞從句虛擬)，這是因它們答案特征相同，即 (should)+動詞原形。eg. He took his umbrella lest it should rain.
大學英語虛擬語氣考題總結:答案的特征
1.(should)+動詞原形(一般式/被動式/否定式)記住信號詞（名詞，動詞，形容詞，分詞等）以及l(fā)est.2. 一般過去時：wish/If only…/would rather/It’s time (high/about) that….
3.基本形式（主要考與過去和將來相反的虛擬語氣）,特別注意時間狀語(混合時間虛擬)
4.倒裝的兩個時間：與過去，與將來相反；三個形式(Had/Were/Should)提前大寫，if省去；
5.but/or/or else/otherwise(跳層虛擬語氣)