资源描述：
《专业英语四级考试语法》由会员上传分享，免费在线阅读，更多相关内容在行业资料-天天文库。
1、名词性从句中的虚拟主语从句(itis+adj./p.pthat)同位语从句(The+n.That)表语从句(n.+bethat)省略if的虚拟法（倒装）(1)虚拟语气中如果从句引导词if/whether省略，从句中需要倒装，提前助动词(系动词）或情态动词。E.g.Ifitshouldraintomorrow,wewouldnotbeabletohavethesportsmeeting.=Shoulditraintomorrow,weshouldnotbeabletohavethesportsmeeting.省略if的虚
2、拟法（倒装）(2)E.g.whetherit(may)befineorrainy,wewouldhavethesportsmeeting.=Beitfineorrainy,wewouldhavethesportsmeeting.Ifshehadbeengivenmoreinformation,shecouldhaveansweredthequestions.=Hadshebeengivenmoreinformation,shecouldhaveansweredthequestions.总结虚拟语气的动词标志"insis
3、t,suggest,require,request,demand,propose,prefer,maintain,move,urge,recommend,command,order"等动词表"建议、愿望"时，其后宾语从句中谓语动词要用虚拟语气。Should+Vwish其后宾语从句中谓语动词要用虚拟语气。{虚拟语气的名词标志1“necessity”或“suggestion”等名词后面的表语从句或同位语从句中的谓语动词要用虚拟语气。2名词word表“命令”时，其后主语从句、表语从句或同位语从句中，谓语动词需用虚拟语气(sh
4、ould)+V。3wish作名词时其后主语从句，表语从句或同位语从句中，谓语动词需用虚拟语气(should)+V。虚拟语气的形容词标志Itis+adj.that句型中出现形容词如necessary,important,vital,decisive,critical,crucial,urgent,strange,desirable,advisable,disappointing,或过去分词充当的形容词如suggested,proposed,advised,demanded,requested,required等时，tha
5、t句中用should+V表示虚拟。虚拟的介词标志Butfor相当于ifithadnotbeenfor。Butforherhelp,Iwouldhavelostmyway.Without,intheabsenceof等组成的短语可相当于一个虚拟的条件从句。Withoutthelightandheatofthesun,whatwouldbecomeofalltheanimalsonearth?Intheabsenceofwater,plantswouldnotgrowwell.Under…condition,也可相当于一个
6、虚拟条件从句。Undermorefavorableconditions,wewouldhavemademoreachievements.错综时间的虚拟条件状语从句中谓语动词的形式可与主句中谓语动词的形式不“配套”，即错综时间的虚拟。IfhehaddoneasIhadsuggestedthen,hewouldn’tberegretfulnow.Iftheyhadn’tfoundusthen,wewouldstillbemissingonthesea.IfIhadn’tmadesufficientpreparationfo
7、rtheexamthen,Iwouldn’tbeincollegenow.虚拟和事实（前虚拟后事实）标志:butE.g.Iwouldhavegonetothepartywithyou,butIwastoobusy.=IfIhadn’tbeentoobusy,Iwouldhavegonetothepartywithyou.（前事实后虚拟）标志:otherwiseE.g.Iwastoobusythen,otherwiseIwouldhavegonetothepartywithyou.MoreInformationwas(w
8、ere)+tohavedone（不定式完成式）表示“原来想做而未做”后面通常but…（陈述语气）。E.g.Iwastohavearrivedhomeontime,butmycarwasheldupbyabadtrafficjam.hadhoped表示过去未实现的愿望，其从句中谓语动词要用虚拟would+V。E.g.Ihadhope
