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第5課
虛擬語氣
一、虛擬語氣的規則用法：
1主、從句都表示與過去事實相反：
從句的謂語動詞用：had + 動詞過去分詞；
主句的謂語動詞用：情態動詞+ have + 動詞過去分詞。
注意：能用于虛擬語氣的情態動詞只有四個：should, could, would, might.
使用哪一個情態動詞要由句子含義決定，考試中出現最多的是could, would.
2 主、從句都表示與現在事實相反：
從句的謂語動詞用：動詞過去式（如果是be則只能用were）
主句的謂語動詞用：情態動詞+ 動詞原形。
3 主、從句都表示與將來事實相反：
從句的謂語動詞用：were to + 動詞原形（重點）、should + 動詞原形、動詞過去式；
主句的謂語動詞用：情態動詞+ 動詞原形。
二、虛擬語氣的特殊應用：
1would rather+ 句子，這時句子謂語動詞用一般過去時來體現虛擬語氣。
2if only 如果，要是...就好了，if only + 句子，這時句子一定要用虛擬語氣。
有兩種形式可以體現虛擬語氣：
a. 如果該句子如果表示與現在或將來事實相反，謂語動詞用一般過去時。
b. 如果該句子如果表示與過去事實相反，謂語動詞用過去完成時。
70. Look at the terrible situation I am in! If only I _B_ your advice.
A follow B had followed C would follow D have followed
47. If only the committee _D_ the regulations and put them into effect as soon as possible
A approve B will approve C can approve D would approve
注意：當if only后的句子表示與現在或將來事實相反，該用動詞過去式來表示虛擬語氣，而選項中又沒有時，可以采用這種形式：would + 動詞原形。
3 當以下動詞后加句子時，句子應用虛擬語氣，句子謂語動詞的形式是：（should）+ 動詞原形。
a. 表示建議、提議的：suggest, advise, propose, recommend, move.
[move只有在表達在會議上提出提議時后面加虛擬語氣]
b. 表示要求的：ask, demand, require, request, desire.
c. 表示指揮、命令的：order,command,direct.
d. 表示堅持，堅持認為的：insist.
4 it is + 第三點中動詞的過去分詞+ that引導的從句。
這樣的結構中從句謂語動詞形式為：（should）+ 動詞原形。
以下幾個形容詞置于該結構中時也要用相同的形式來體現虛擬語氣：
important, necessary, essential, obligatory（有義務的，強制性的，必須的）。
5 第三點中動詞相應的名詞形式+ that引導從句，該從句同樣要用虛擬語氣，
謂語動詞形式為：（should）+ 動詞原形。
經常用于這種結構的詞有：suggestion, advice, proposal, recommendation, motion.
6 以下一些表達方式所在的句子一定要用虛擬語氣。
or(表示否則), otherwise, unless, but for(若不是，若非)
當遇到含有以上四個表達方式的句子時，先要判斷該句是表示與現在、過去、還是將來事實相反，然后依照相應的虛擬語氣規則用法的形式來確定句子結構。
含有下面三個表達方式的句子體現虛擬語氣的形式是固定的：
lest(以免，防備), for fear that(惟恐), on condition that(在..條件下)
它們后面句子的謂語動詞的形式都是：（should）+ 動詞原形。
7 it is time 是...的時候了。
這個結構有以下兩種變形形式，所用虛擬語氣形式都一樣：it is high time / it is about time.
這三個結構后面加的句子謂語動詞都用一般過去時來體現虛擬語氣。
8 注意以下兩種情況下should + 動詞原形中should不能省略。
這里should表示一種語氣，經常被翻譯成“竟然”。
a. 四個動詞：think, believe, expect, suspect.
它們的否定或者疑問形式后面加句子，句子謂語動詞用：should + 動詞原形，should不能省略。
I don't believe that he should be cheated. 我不相信他也會被騙。
b. it is a pity, it is a shame 真遺憾，it is strange 真怪
以上三個結構后面加的句子謂語動詞用：should + 動詞原形，should不能省略。
錯綜時態的虛擬語氣
錯綜時態的虛擬語氣即指主句和從句在表達是與什么時態的事實相反上并不一致（比如主句要表達與現在事實相反而從句要表達與過去事實相反），這種情況要采用“對號入座”的方法來處理，即主從句結構分別采用與其表達時態對應的結構。
60. If I hadn’t stood under the ladder to catch you when you fell, you _A_ now.
A wouldn't be smiling B couldn't have smiled C won't smile D didn't smile
2. If you had studied the problem carefully yesterday, _C_.
A you won’t find any difficulty now B you would not have found any difficulty now
C you would not find any difficulty now D you have not found any difficulty now
3. He would be studying at the university now if he _C_ the entrance examination.
A passed B have passed C had passed D should have passed
16.It is a shamethat he _B_ that poor little girl!
A deceived B should deceive C deceive D deceiving
18. Mrs. bliss kept the door and the windows shutlestthe noise outside _D_ her son's sleep. [lest(以免，防備) 后面句子的謂語動詞的形式都是：（should）+ 動詞原形]
A would interfere with B had interfered with
C interfered with D should interfere with
-------------------------1996-01-------------------------
21. The fifth generation computers, with artificial intelligence, _C_ and perfectednow.
A) developed B have developed C are being developed D will have been developed
22. This ticket _C_ you to a free meal in our new restaurant.
A gives B grants C entitles D credits
A,B兩項都要加雙賓語，結構為：gives / grants sb. sth.
entitle sb. to sth. 使某人有權得到某物；credit A to B 相信A是由B造成的。
相信飛機失事是由飛行員錯誤造成的。Credit the crash to the pilot's mistake.
crash 墜落，墜毀（專指飛機失事）；collision 碰撞（強調兩個物體碰撞，如火車、汽車等）。
we are sorry, very sorry, terribly sorry, awfully sorry.
23. You _D_ her in her office last Friday; she's been out of town for two weeks.
A needn't have seen B must have seen
C might have seen D can't have seen
