課程內容
高中英語《藝術 Unit 1 Art(Part 4)》（選修6）

一、語氣的分類
英語的動詞一般可帶三種不同的語氣：陳述語氣，祈使語氣和虛擬語氣。不同的語氣用動詞的不同形式來表示。
陳述語氣
I went to the thearte yeaterday.
Jack hasn't come back home yet.
祈使語氣
Let's go.
Don't touch anything on the table until the bell rings.
虛擬語氣
If I were you,I would not leave her alone.
Our teacher suggested that we go to the library this afternoon.
(The Subjunctive Mood)表示說話人所說的話不是事實，二十一種假設，愿望，懷疑或推測，虛擬語氣主要用于if條件狀語從句，也可用于名詞性從句等。
條件句表示主句的條件，分真實條件句和虛擬條件句兩種。
a 真是條件句表示條件時真的或有可能實現(xiàn)的，采用陳述語氣。
b 虛擬條件句 表示條件是無法實現(xiàn)或幾乎無法實現(xiàn)的，采用虛擬語氣。
二、“if”虛擬條件句的概念
由"if"引導的虛擬條件句叫作“if"虛擬條件句
I could easily recognize if I had seen him before.
其他虛擬條件句
Without your help,I could't have finished my work on time.
三、if Sentence Structure
"if"虛擬條件句的結構
a 表示與現(xiàn)在事實相反的假設
b 表示與過去事實相反的假設
c 表示與將來事實相反的假設
虛擬語氣
1.虛擬語氣用于條件狀語從句中
（1）表示與現(xiàn)在事實相反的假設，條件狀語從句中的謂語動詞用“過去式（be動詞的過去式用were)”,而主句中的謂語動詞“would/should/could/might+動詞原形”。
If I were a boy,I would join the army.
What would you do if you won the lottery?
If I won the lottery,I would...
If I won the lottery,I would buy an expensive car.
If I had a lot of money I would buy a villa.
If I had a lot of money now,I would travel around the world.
If it were fine now,I would go shopping.
Practice 1:Fill in the blanks
a If they were (be) here,they would take(take)your advice.
b If the world-war burst(burst) out again,what would happen(happen) to our people on earth?
c If the policeman were not(be not)in that room,it could be (be) very dangerous.
d If I were (be)in your position,I would ask(ask) for teacher's help.
2.與過去的事實相反
從句的謂語用had+過去分詞，構成If I (we,you,he,they)+had+過去分詞的形式；主句的謂語用should(第一人稱）/would(第二、三人稱）/could/might have+動詞過去分詞
If he had driven more carefully,he would not have had the car accident yesterday.
Practice 2:Fill in the blanks
a If Tom had been (be)more careful in the exam,he would have passed(pass) it already.
b If you had not (get)up earlier,you would have caught (catch)the first train.
c If I had met(meet) you yeaterday,we would have gone(go) to the concert together.
3.與將來事實相反
從句的謂語用If I (we,you,he,they)+過去分詞的形式或were to do或should do形式，主句謂語用should(第一人稱）/would(第二、三人稱）/could/might +動詞原形
假如他來了，我們對他說什么呢？
If he were to come,what should we say to him?
假如他看見我，就會認識我。
If he should see me,he would know me.
Practice 3:Fill in the blanks
a If there should be(be) no natural resource any more,we should make(make)use of nuclear power.
b What would happen(happen) if you should get up (get up)too late tomorrow?
c If Robots were to control(control) the world some day,here would be(be)no friendship.
主句與從句的動作發(fā)生在不同的時間，這時主從句謂語動詞的虛擬語氣形式因時間不同而不同，這叫做混合條件句。
例句中從句與過去事實相反，主句與現(xiàn)在事實相反
If you had asked him yesterday,you would know what to do now.
一、虛擬語氣在條件狀語從句中的用法
條件從句：現(xiàn)在      If 從句的謂語形式：過去時（were)     主句的謂語形式   would/could/should/might+v.(原）
條件從句：過去      If 從句的謂語形式：過去完成時     主句的謂語形式   would/could/should/might+have+p.p.
條件從句：未來      If 從句的謂語形式：1.過去時  2.should+v.  3.were to do      主句的謂語形式   would/could/should/migh+v.(原）
二、虛擬語氣在賓語從句中的用法
1.在動詞wish 后的賓語從句中，表示與現(xiàn)在或過去的事實相反、或對將來的主觀愿望，從句通常省略連詞that
1)表示對現(xiàn)在情況的虛擬：從句動詞用過去式或過去進行式（be動詞一般用were）。
（2）表示對過去情況的虛擬：從句動詞常用'had+過去分詞”
（3）表示對將來的主觀愿望：從句動詞形式為："would+動詞原形”
注意：主句的主語與從句的主語不能相同，因為主句的主語所期望的從句動作能否實現(xiàn)，取決于從句主語的態(tài)度或意愿（非動物名詞除外）
二、在表“建議”“命令”“計劃”“要求”等含義的動詞的賓語suggest,propose,demand,request,require,order,insist等動詞后的賓語從句中，謂語為“(should) do"形式。
例如：
I suggest/propose/demand/request/require/order/ that he(should)be sent to the nearsest hospital as soon as possible.
注意：當suggest 表示“暗示”之意時，則不用虛擬語氣；當insist表示“堅持認為”之意時，則也不用虛擬語氣。
關于虛擬語氣 辨析1
虛擬語氣的誤用辨析：
1.（誤）I shouldn't do that if I was you.
(正） I shouldn't do thst if I were you.
如果我是你，我不會那么做。
表示與現(xiàn)在事實相反的虛擬語氣不能用was,只能用were.
關于虛擬語氣 辨析2
2.(誤）If my father were here now,he will tell me what to do.
(正）If my father were here now,he would tell me what to do.
如果我父親現(xiàn)在在這兒，他會告訴我怎么做。
表示與現(xiàn)在事實相反的虛擬語氣中，主句的助動詞只能用would,might 等過去時。
關于虛擬語氣 辨析3
3.（誤）If I knew her telephone number,I would have called her.
(正）If I had known her telephone number,I would have called her.
如果我知道她的電話，我就給打了。
表示與過去事實相反的虛擬語氣中，條件從句的動詞要用過去完成時。
關于虛擬語氣 辨析4
4.（誤）If it had not rained yeaterday,he might come.
(正）If it had not rained yeaterday,he might have come.
如果昨天不下雨，他可能就來了。
表示與過去事實相反的虛擬語氣中，主句的動詞要用助動詞的過去時might 或could+have+過去分詞。
關于虛擬語氣 辨析5
5.（誤）I don't think that I shall fail.But if I fail,I would try again.
(正）I don't think that I shall fail.But if I should fail,I would try again.
我認為我不會失敗，但要是我失敗了，我會再努力。
表示與未來事實相反的虛擬語氣中，條件從句的動詞用shold 加動詞原形。
Homework
句型練習（用If I were you 句型翻譯下下列句子）
1.我要是你的話，我就會把英語學好。
2.如果你昨天來，你就會看見他。
3.萬一明天下雨，我們就不到那兒去。
4.我希望我十年前就認識他。
5.他對待我就像對待他自己的兒子一樣。