if引導(dǎo)的條件句中的虛擬語氣

1、if 引導(dǎo)的條件句中的虛擬語氣虛擬語氣表示一種不能實(shí)現(xiàn)的假設(shè)。該語法主要用于if 條件狀語從句。一、 if 引導(dǎo)的條件狀語從句的分類及虛擬條件句的判斷1、可以把條件句分為兩類：1).真實(shí)條件句（ Sentences of Real Condition ）：凡是假設(shè)的情況發(fā)生性可能很大，就是真實(shí)條件句。例如：、If I have time , I willhelp you with this work. 如果我有時(shí)間會(huì)幫助你做此工作的。(2)、If time permits, we'll go fishing together.(如果有時(shí)間的話，我們就一起去釣魚。）2).虛擬條件句 （

2、Sentences of Unreal Condition ）：當(dāng)假設(shè)是不大可能實(shí)現(xiàn)時(shí)，就是虛擬條件句。例如：、If I were you , I would have attended the meeting. 如果我是你的話，就去參加會(huì)議了。、 If he had come here yesterday, he would have seen his old friend.假如他昨天來這兒的話，就會(huì)看見他的老朋友。、 If it had rained yesterday, we would have stayed at home.（如果昨天下雨的話，我們就會(huì)留在家里。）2、.if 條件狀語

3、從句中虛擬語氣的判斷判斷是真實(shí)條件句還是非真實(shí)條件句。只有在非真實(shí)條件句中才使用虛擬語氣。通過句子意思，看假設(shè)的條件是否能夠?qū)崿F(xiàn)，能精選文庫夠?qū)崿F(xiàn)是真實(shí)條件句，不能使用虛擬語氣； 假設(shè)的條件不能實(shí)現(xiàn)則是非真實(shí)條件句，要用虛擬語氣。判斷這個(gè)假設(shè)是與哪個(gè)事實(shí)相反。通常有三種情況： 與過去事實(shí)相反。與現(xiàn)在事實(shí)相反。與將來事實(shí)可能相反。3、“后退一步法 ”后退一步法是指在準(zhǔn)確地判斷了該句與哪一事實(shí)相反后， 按虛擬語氣的后退一步法處理從句謂語動(dòng)詞的時(shí)態(tài)。 即：在非真實(shí)條件狀語從句中，謂語動(dòng)詞按正常情況 “后退一步 ”。也就是：與過去事實(shí)相反，在從句中用過去完成時(shí)形式表示。與現(xiàn)在事實(shí)相反，在從句中用過去一

4、般時(shí)形式表示。與將來事實(shí)可能相反，在從句中用過去將來時(shí)形式表示。主句中則用情態(tài)動(dòng)詞 would, should, could 等加一個(gè)與從句一致的動(dòng)詞形式。例：、 If I had come her yesterday, I would have seen him.、 If I were a teacher, I would be strict withmy students.、 If it should snow tomorrow, they couldn't go out.4、注意事項(xiàng) if 條件句中如有 were, should, had，可以省去 if ，并使用倒裝語序。在現(xiàn)代

5、英語中 if 條件狀與從句中的謂語動(dòng)詞如果是 be 其過去形式一般用 were。-2精選文庫二、虛擬語氣在if 引導(dǎo)的條件句中的用法：（一）、表示與現(xiàn)在事實(shí)相反的情況。其句子結(jié)構(gòu)為：從句： if + 主語 + 動(dòng)詞的過去式 (be 用 were) +主句：主語 + would (should, could , might) + 動(dòng)詞原形 +例：1.If I were you, I would go with him.2.If the weather were fine, I would go there.如果天氣好，我去那兒。（事實(shí)天氣不好）3.If I were you, I would r

6、ead it again.如果我是你的話，我再讀一遍。（事實(shí)上我不是你）4.If time permitted, I would write it again.如果時(shí)間允許的話，我再寫一遍。（事實(shí)上時(shí)間不允許）5.If it weren snowing,t we wouldn stay in the house.要是現(xiàn)在不下雪的話， 我們就不會(huì)待在屋里。 （事實(shí)上現(xiàn)在下雪）6.What would I do if I were in your place?要是我處于你地位我會(huì)怎么辦？（事實(shí)上我不在你的位置上）7.If he hurried, he could catch the first b

7、us.他要是快點(diǎn)能夠趕上頭班公共汽車。（可是他不著急）8.If it weren fort your help, we would get into trouble.如果沒有你們的幫助，我們就會(huì)陷入困境。（而事實(shí)上得到了你們的幫助）9.If we had the manpower, we could open up even more land.-3精選文庫如果有人力 ,我們還能開更多的荒地.10. If I were you, I would go with him.(從句 If I were you, 主句 I would go with him.)11. If I were you, I should buy it.(從句用過去式動(dòng)詞were，主句用動(dòng)詞原形buy)12. If I had time, I would study French.(如果有時(shí)間，我會(huì)學(xué)習(xí)法文。）（從句用過去式動(dòng)詞had，主句用動(dòng)詞原形study）13. If she knew English, she would not ask me for help.(如果她懂英文， 她就不必要我?guī)土恕?)(從句用過去式動(dòng)詞knew,主句用動(dòng)詞原形ask)注意：如果動(dòng)作在進(jìn)行中，主句要用："主語 +