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1、Unit3Unit3UnderstandingeachotherUnrealconditionals虛擬語氣中的非真實(shí)條件句Grammarandusage虛擬語氣可用于條件句和其它一些從句中。虛擬語氣用于條件句中比較多，情況也比較復(fù)雜，所以要特別加以注意。首先要判斷一下是否應(yīng)該用虛擬語氣，因?yàn)闂l件句分為兩種，一種是真實(shí)條件句，一種是非真實(shí)條件句，只有在非真實(shí)條件句中才用虛擬語氣，在真實(shí)條件句中，要用陳述語氣。虛擬語氣的介紹Observethefollowingsentencesandtellwhethertheyarerealorunrealconditionalclaus
2、es.Ifwegoonpollutingtheworld,itwon’tbefitforustolivein.Ifyouarebusydoingyourhomework,Iwon’tinterruptyou.Ifyouhavefinishedcleaningtheclassroom,youcangohomenow.(Undertheseconditions,thethingsaresuretohappen.)Iftherewerealotofgoodrestaurantsinthecity,thiswouldmakeitmoreattractive.(Therearen’t
3、manygoodrestaurantnow.)IfalotofpeoplespokeEnglish,itwouldbeveryhelpfulfortourists.(NotmanypeoplecanspeakEnglishnow.)非真實(shí)條件句的時(shí)態(tài)表達(dá)如果假設(shè)的情況完全不存在或者實(shí)現(xiàn)的可能性很小,可以說幾乎沒有時(shí),就需要用虛擬語氣來表達(dá),也就是說,這時(shí)的條件句是非真實(shí)的條件句。此時(shí)的句子時(shí)態(tài)比真實(shí)條件句中的時(shí)態(tài)后退一步。虛擬語氣條件從句和主句中的虛擬語氣時(shí)間從句主句與現(xiàn)在事實(shí)相反If+主語+動(dòng)詞的過去式(be-were)…與過去事實(shí)相反If+主語+had+過去分詞主語+s
4、hould/would/could/might+動(dòng)詞原形主語+should/would/could/might+have+過去分詞與將來事實(shí)相反If+主語+wereto/(should)+動(dòng)詞原形主語+should/would/could/might+動(dòng)詞原形注意：在ifI/he/she/it之后，可用were代替was。兩者在意義上沒有區(qū)別，但是were更為正式，特別是在陳述心存懷疑的事情時(shí)，如：Ifshewereready,wewouldgo.在與將來事實(shí)相反的條件從句中，我們可以用wereto或should+do來表示,如:IfIweretofailmyEnglish
5、test,Iwouldhavetotakeitagainattheendoftheterm.Ifheshouldcometomorrow,Iwouldtalktohimaboutit.在非真實(shí)條件句中，如果有were，had，should，我們可以將if省略，把這些詞置于句首，采用倒裝形式，如:IfIshouldmeether,Iwouldtellher.=ShouldImeether,Iwouldtellher.虛擬條件句中的省略與倒裝IfIwereinyourposition,Iwoulddoitbetter.=WereIinyourposition,Iwoulddoi
6、tbetter.Iftheyhadmadepreparations,theywouldhavesucceeded.=Hadtheymadepreparations,theywouldhavesucceeded.有時(shí)非真實(shí)條件句中，主句謂語動(dòng)詞所表示的動(dòng)作和條件從句中謂語動(dòng)詞所表示的動(dòng)作并不同時(shí)發(fā)生，這時(shí)動(dòng)詞的形式并不完全按照上述表格來進(jìn)行，而需要按照各自的時(shí)間來調(diào)整，這樣的句子就叫錯(cuò)綜時(shí)間條件句。錯(cuò)綜時(shí)間條件句e.g.Ifyouhadfollowedthedoctor’sadvice,thenyouwouldbeallrightnow.IfIhadn’tfinishedmy
7、compositionbynow,Iwouldbeworkingonittomorrow.Ifshehadpreparedwellforherlessonsyesterday,shewouldn’thavesomanydifficultiesnow.有時(shí)一個(gè)假設(shè)的情況并不用條件從句表示,而用其它方式來表示,這樣的句子叫含蓄條件句。用with，without等介詞短語或分詞短語或者獨(dú)立主格結(jié)構(gòu)來代替條件從句。含蓄條件句e.g.Wemighthavediedwithoutyourhelp.=Wemighthavedie
