会计学概念：谓语v用不同的形式表示说话人的不同意图，这种形式称为语气。语气分三种：1.陈述语气：用来陈述一个事实，或提出一种看法，有肯定、否定、疑问、感叹等形式。Heislateforclass.Whatfun!Heisnotinterestedinclassicalmusic.2.祈使语气：用来表示请求、邀请、命令、警告或劝告等（动词常用原形）Don’tbelate！3.虚拟语气：表示说话人所说的不是事实，而是一种假设、愿望(yuànwàng)、怀疑或推测。一、虚拟语气在if非真实(zhēnshí)条件句中Ifyouhadstudiedhardbefore,youwouldhavepassedtheexam.IfI____(visit)myfutureuniversitytomorrow,I___(take)lookatthelibraryfirst.Youdidn’tletmedrive.Ifwe______inturn,you______sotired.drove;didn’tgetdrove;wouldn’tgetweredriving;wouldn’tgethaddriven;wouldn’thavegot________itraintomorrow,wewouldhavetoputoffthevisittotheYangPuBridge.WereB.ShouldC.WouldD.Will注意：1.错综时间虚拟语气当从句主句所表示的行为所发生的时间不一致时，动词的形式要根据它所表示的时间作出相应(xiāngyīng)的调整。Ifyou____________(follow)myadvicejustnow,you_________(be)betternow.Ifyou__________(study)hardbefore,you_______(be)acollegestudentnow.Ifyou______withGeorgeearlier,you_____soangrynow.talked;wouldnotbehadtalked;wouldnotbewouldtalk;wouldnotbehadtalked;wouldnothavebeenIfwehadtakensucheffectivemeasuresmuchearlier,theriver_____soseriouslynow.isnotpollutedwouldnotbepollutedhadnotbeenpollutedwouldnothavebeenpollutedMaybeifI_____science,andnotliteraturethen,Iwouldbeabletogiveyoumorehelp.(北京(běijīnꞬ)卷)studiedwouldstudyhadstudiedWasstudying-Theweatherhasbeenveryhotanddry.-Yes.Ifithadrainedevenadrop,thingswouldbemuchbetternow!Andmyvegetables___.(北京(běijīnꞬ)卷)would’tdiedidn’tdiehadn’tdiedWouldn’thavedied2.if从句中，were，had（完成时态标志），should可以放在句首，（用于倒装结构），if必须(bìxū)省略。否定词not不能放在前面。1.HadInotseenhimthen(Hadn’tIseenhimthen),Iwouldn'thavebeenveryhappy.______hard,hewouldhavepassed.IfheweretoworkHadheworkedShouldheworkWerehetowork3、含蓄虚拟语气有时为了(wèile)表达的需要，在虚拟语气中，并不总是出现if引导的条件句，而通过其它手段来代替条件句。常用的有介词with，without，butfor（倘没有，要不是）；连词or，but；副词otherwise等。2.Hetelephonedtoinformmeofyourbirthday,orIwouldhaveknownnothingaboutit.3.Ishouldhavegivenyoumorehelp,butIwastoobusy.Withoutelectricity,humanbeinglife______quitedifferenttoday.iswillbewouldhavebeenwouldbeButforhishelp,I______.shouldnoth