語氣-虛擬語氣

語氣是以動詞形式表現(xiàn)出來的語法特征，它表示說話人對事物所持的態(tài)度。

1）陳述語氣：用來陳述事實(shí)的，有肯定，否定，疑問或感嘆等形式。
She is very clever.
What fun it is to swim in the lake!
Why don’t you join an English language club to practice speaking English?             
2) 祈使語氣: 用來表示請求，命令或勸告等。 
   Don’t be late for the meeting.
3）虛擬語氣:：表示所說的內(nèi)容與事實(shí)不符，不是事實(shí)或是不可能發(fā)生的，只是
   一種愿望，建議或與事實(shí)相反的假設(shè)等。
真實(shí)條件句 
真實(shí)條件句用于陳述語氣，假設(shè)的情況可能發(fā)生，其中 if 是如果的意思。
　 
　　時態(tài)關(guān)系
句型： 條件從句　　　 主句
　　 一般現(xiàn)在時　　 shall/will + 動詞原形
　If he comes, he will bring his violin.
典型例題
　The volleyball match will be put off if it ___.　
A. will rain　 B. rains　 C. rained　 D. is rained
　答案B。真實(shí)條件句主句為將來時，從句用一般現(xiàn)在時。
非真實(shí)（虛擬）條件句 
1）時態(tài)：可以表示過去，現(xiàn)在和將來的情況。它的基本特點(diǎn)是時態(tài)退后。
a.同現(xiàn)在事實(shí)相反的假設(shè)。
句型 ： 條件從句　　　主句 
　　一般過去時　　　should( would) +動詞原形
　 If they were here, they would help you.
b.表示與過去事實(shí)相反的假設(shè)。
句型： 條件從句　　　 主句　　　
　　　過去完成時　　　 should(would) have+ 過去分詞
　 If she had worked harder, she would have succeeded.　　
　 The rice would not have been burnt if you had been more careful.　 
　 If my lawyer had been here last Saturday, he would have prevented me from
   going. 
   If he had come yesterday, I should / would have told him about it.
　 含義：He did not come yesterday, so I did not tell him about it.
　 If he had not been ill and missed many classes, he would have made greater
   progress.
　 含義： He was ill and missed many lessons, so he did not make greater progress.　
c. 表示對將來的假想
　句型：　 條件從句　　　　 主句
　　 一般過去時　　　 should+ 動詞原形
　　 were+ 不定式　　 would + 動詞原形
　　 should+ 動詞原形
　If you succeeded, everything would be all right.
　If you should succeed, everything would be all right.
　If you were to succeed, everything would be all right.
wish的用法 
1）用于wish后面的從句，表示與事實(shí)相反的情況，或表示將來不太可能實(shí)現(xiàn)的愿望。其賓語從句的動詞形式為：

　　　　　　　  真實(shí)狀況　wish后　　 　
從句動作先于主句動詞動作　　現(xiàn)在時　　過去時
（be的過去式為 were）　　　　　　　　　 　
從句動作與主句動作同時發(fā)生　過去時　　過去完成時
（had + 過去分詞）　　　　　　　　　　
將來不大可能實(shí)現(xiàn)的愿望　　　將來時　would/could + 動詞原形　　
  I wish I were as tall as you.　我希望和你一樣高。
 He wished he hadn‘t said that. 他希望他沒講那樣的話。
 I wish it would rain tomorrow. 我希望明天下雨就好了。
2）Wish to do表達(dá)法。
　 Wish sb / sth to do
　 I wish to see the manager. = I want to see the manager.
　 I wish the manager to be informed at once. (= I want the manager to be informed 
   at once.)
在由as if, so that, in order that 等引導(dǎo)的狀語從句中也常用虛擬語氣。 
She loves these children as if they were her own.
The teacher spoke slowly so that the students can/ may /could /might hear her  
clearly.
She gave us some money in order that we might finish the work earlier.