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1、Unit3Unit3UnderstandingeachotherUnrealconditionals虛擬語氣中的非真實條件句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,因為條件句分為兩種,一種是真實條件句,一種是非真實條件句,只有在非真實條件句中才用虛擬語氣,在真實條件句中,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.)非真實條件句的時態(tài)表達如果假設(shè)的情況完全不存在或者實現(xiàn)的可能性很小,可以說幾乎沒有時,就需要用虛擬語氣來表達,也就是說,這時的條件句是非真實的條件句。此時的句子時態(tài)比真實條件句中的時態(tài)后退一步。虛擬語氣條件從句和主句中的虛擬語氣時間從句主句與現(xiàn)在事實相反If+主語+動詞的過去式(be-were)…與過去事實相反If+主語+had+過去分詞主語+s
4、hould/would/could/might+動詞原形主語+should/would/could/might+have+過去分詞與將來事實相反If+主語+wereto/(should)+動詞原形主語+should/would/could/might+動詞原形注意: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,如:Ifshewereready,wewouldgo.在與將來事實相反的條件從句中,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.有時非真實條件句中,主句謂語動詞所表示的動作和條件從句中謂語動詞所表示的動作并不同時發(fā)生,這時動詞的形式并不完全按照上述表格來進行,而需要按照各自的時間來調(diào)整,這樣的句子就叫錯綜時間條件句。錯綜時間條件句e.g.Ifyouhadfollowedthedoctor’sadvice,thenyouwouldbeallrightnow.IfIhadn’tfinishedmy
7、compositionbynow,Iwouldbeworkingonittomorrow.Ifshehadpreparedwellforherlessonsyesterday,shewouldn’thavesomanydifficultiesnow.有時一個假設(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立主格結(jié)構(gòu)來代替條件從句。含蓄條件句e.g.Wemighthavediedwithoutyourhelp.=Wemighthavedie