2015會考書面表達寫作指導：虛擬語氣語法
一.虛擬語氣用於條件狀語從句中
1. 表示與現在事實相反或不可能發生：條件狀語從句：一般過去時(虛擬語氣中be→were)主句用：would(should, could, might)+動詞原形。
If we had time now, we would read it again.
If I were you, I would work hard.
2. 表示與過去事實相反或不可能發生：條件狀語從句：had+過去分詞;主句：would(should, could, might)+have+過去分詞。
If he had taken my advice, he would have succeeded in the test.
If I had known your telephone number then, I would have called you.
3. 表示與將來的事實可能相反或不可能發生：條件狀語從句：①一般過去時②should +動詞原形③were to+動詞原形;主句：would(should, could, might)+動詞原形。
If it should rain, the crops would be saved.
If it were to snow tomorrow, they would not go out.
P.S 虛擬條件句的特殊情況
(1). 混合/錯綜型虛擬語氣
當條件狀語從句表示的行為和主句表示的行為所發生的時間不一致時，稱為‘錯綜條件句’，動詞的形式要根據它所表示的時間作出相應的調整。
If you had followed my advice, you would be better now.(從句說的是過去，主句是現在)
If I were you, I would have taken his advice.(從句是現在，主句是過去)
(2)省略if的虛擬語氣
如果從句中含有were/ should/ had時，則可以把這三個詞置於句首，省略if.採用倒裝語序。
If it should happen, what would you do? →Should it happen, what would you do?
If he had recognized me, he would have come over. →Had he recognized me, he would have come over.
(3) 含蓄虛擬條件句
有時候假設的情況不以if引導的條件從句形式表現出來，而是通過一個介詞短語，連詞或其他形式表示。常用的詞或短語有：without, with, but for(要是沒有), otherwise, or, but等。
Without your help(=If we had not had your help), we could not have succeeded.
But for electricity(=If there were no electricity, there would be no modern industry.
He felt very tired yesterday, or/ otherwise he would have attended the party.
(4) 在if it were( had been )not for ….句型中的虛擬語氣
虛擬語氣也常用於‘if it were/(had been) not for ….’句型中，意為‘要不是由於…’。
If it were not for peace, we could not be living a happy life today.
If it had not been for your timely help, I would have gone bankrupt.
二.虛擬語氣用在名詞性從句中
1.主語從句中的虛擬語氣
這種虛擬語氣主要用在it is+形容詞(名詞，過去分詞)+that+主語+should+動詞原形(should可以省略)這種結構中。
常見的這類形容詞有：advisable, anxious, better, desirable, surprising, natural, necessary, strange, important, regretful.
常見的這類過去分詞有：decided, demanded, recommended, requested, desired, required, ordered, suggested.
常見的這類名詞有：duty, pity, no surprise, no wonder, regret, shame.
It was suggested that he(should)join the club activities.
It is strange (surprising, disappointing) that she (should) not have been invited.
It is a pity that he (should) refuse to accept the offer.
2. 賓語從句中的虛擬語氣
①wish 後面所跟賓語從句謂語動詞用虛擬語氣(意為要是，但願…就好了)，其形式主要有三種：
表示對現在情況的虛擬：wish後接一般過去時的從句
表示對過去情況的虛擬：wish後接過去完成時/should，could have done
表示對將來情況的虛擬：wish後接would，could+動詞原形
Iwish it were spring all year round.
I wish it would be fine tomorrow.
She wished she had stayed at home.
②在表示建議，命令，要求等動詞後的從句要用(should)+動詞原形。此類動詞有：suggest, advise, propose, demand, require, insist(要求), order, prefer, command, ask, request.
The teacher ordered that all the books (should) be handed in on time.
P.S. 當suggest表示‘暗示，說明’之意;insist表示‘堅持認為，堅持說’之意時，從句不用虛擬，用正常的陳述語氣。
The man insisted that he had never stolen the money.
The smile on his face suggested that he was satisfied with life.
3. 表語從句和同位語從句中的虛擬語氣
在表示建議，命令，要求的名詞後的表語從句或同位語從句中的`謂語動詞要用(should)+動詞原形。常見名詞有：advice, desire, request, demand, proposal, suggestion, preference, requirement, order.
He gave orders that the guests (should) be hospital entertained.
His proposal is that we (should) get rid of the bad habits.
三.虛擬語氣在其他情況中的使用
1.在as if/ as though引導的狀語從句中，若從句與事實相反，則要用虛擬語氣。其形式如下：
主語+as if/ though +主語+一般過去時(從句的動作與主句同時發生)
主語+as if/ though +主語+would/could+動詞原形(從句的動作相對主句來說在將來發生)
主語+as if/ though +主語+過去完成時(從句的動作先發生於主句動作之前)
He talks as if he knew all about it.
She speaks English well as if he had studied in America.
He learns English so hard as if he would go abroad.
2.在it is (high) time that …句型中也用虛擬語氣，從句常用過去式，有時也用should +動詞原形，表示早該做而沒做的事，含建議的意味。
It is time that we went home.
P.S.此句型中，注意與‘It/This is the +序數詞+time that+現在完成式的區別。
This is the first time that I have been here.
d rather後接動詞原形，但接從句時要用虛擬語氣(寧願，但願)。
Would rather +主語+一般過去時(表示與現在或將來相反)
Would rather +主語+過去完成時(表示與過去相反)
I’d rather he didn’t go now.
I’d rather you hadn’t done it.
4. if only後接從句也用虛擬語氣，其形式與wish的用法一致。
5. 動詞hope, intend, mean, plan, want, think等詞用過去完成的形式，表示的意思為‘本想，本打算，本認為’
He had meant to buy the furniture last week, but it rained.
(他上週本打算去買那件傢俱，但卻下雨了)
