图文高中英语语法if条件句If - Clauses

IFClausesToexpressaconsequencedependingonacondition,weusetheconditional,whichconsistsofan

IFclause.TheIFclausecanprecedeorfollowthemainclause.Whenthe

IFclausecomesfirst,acommaisplacedbetweenthetwoclauses.Ifclause(condition)Mainclause(consequence)Ifyoubookyourholidayinadvance,yougetadiscount.Dependingonthelevelofprobability(certain,probable,possibleorpurelytheoreticalconditions)differenttensesareusedintwopartsoftheconditional.Therearefourtypesofconditional:typezero,one,twoandthree,whichwearegoingtoexplain.TYPEZEROIntheIFclauseofthezeroconditional,wedescribeaconsequencethattakesplaceregularlyandwithcertainty.Ifclause:if+presentsimpleMainclause:presentsimpleIfIdrinkcoffeeintheevening,Ican’tgothesleep.Ifclause:if+presentsimpleMainclause:presentsimpleIfunemploymentisrising,peopletendtostayintheirpresentjobs.Ifclause:if+presentsimpleMainclause:presentsimpleIfyouvisitLondon,goontheLondonEye.Thezeroconditionalisusedto:expressgeneraltruths,scientificandmathematicallaws,technicalprocedures,instructions.Thedaysgetlongerifyoutravelnorth.Ifyoupressthiskey,thedisplaylightsup.giveadvice.Inthiscase,thepresentformofimperativeormodal(canormay)isusedinthemainclauseGo/Youcangotobedifyoufeeltired.TYPEONEInthefirstconditional,wedescribearealpossibility.Wetalkaboutfactsthat,givencertainconditions,probablyorpossiblywilltakeplaceinthefuture.Inthiscase,theverbtensesareusually:Ifclause:if+presentsimpleMainclause:will/’ll/won’t+baseformIfitdoesn’train,we’llhaveabarbecueinthegardentomorrow.IfIfindheraddress,Iwillsendheraninvitation.

IfIdon’tseehimthisafternoon,Iwillphonehimintheevening.NOTE:IntheIFclauseitispossibletouseeitherthepresentsimpleorthepresentcontinuous.Ifyoucometomyhouse,I’llshowyoumypaintings.Ifyouarestayingovernight,I’lltrytofindyouaroom.Inthemainclause,theuseofwillindicatesacertainconsequence.Toindicatethatsomethingispossible,weusemodalcan,whileforanuncertainconsequenceweusethemodalmay.Ifyouspendtoomuchtimeinthesun,youmaygetsunburnt.(itisn’tcertain)TYPETWOWhenweassumeaconditiontobeimprobableorimaginaryandthatwedon’texpecttohappenbutishowever,theoreticallypossible,wecanusethesecondconditional.IfIwonamilliondollarsonthelottery,IwouldstopworkingandwouldgoandliveintheCaribbean.(itishighlyunlikelybutishoweverpossible)Thesecondconditionalisalsousedwhenproposeadifferentsituationtothepresentreality.Ifyouworkedharder,yourgradeswouldbemuchbetter.(situationthatisdifferenttothepresentreality:atthemomentyouaren’tworkinghardenough)Thestructureofthesecondconditionalis:Ifclause:if+pastsimpleMainclause:would/’d/wouldn’t+baseformIfIhadmyowncar,Iwoulddrivetowork.IfIfoundheraddress,Iwouldsendheraninvitation.IfIhadalotofmoney,Iwouldn’tstayhere.Notehowthesecondconditionalisstructuredinthequestionform:Ifyouwonsomebigmoney,wouldyouspenditallorwouldyousavepartofit?Whentheverbbeispresentinanifclause,wereisusedforallpersons.InspokenEnglish,wasisalsousedforthefirstandthirdpersonsingular:IfI/he/she/itwere.....was......

Hewouldmakeaverygoodcareerifhewas/werealittlemoreambitious.TheexpressionsIfiwereyou/him/her....isusedtogiveadviceandwarnings.IfIwereyou,I’dtalktoher.Inamainclauses,asanalternativetowould,othermodalscanbefoundsuchas:couldtoexpressabilityorpossibility,mighttoexpressuncertaintyandshouldtoexpressapieceofadvice.

Ifyouplayedamusicalinstrument,youcouldjointhelocalbend.IfshetriedJapanesefood,shemightfindthatshelikesit.IfIshouldwintherace,Ishouldthankthecoachforhishelp.Themodalswould,shouldorcouldareoftenfoundinifclauses.

Wouldisusedinifclausestoexpressarequestinapoliteandformalway,oreventoexpresswillingnesstodosomething.Ifyouwouldkindlytellthemanager,Iwouldreallybegrateful.Theuseofshouldinifclausesmakesthehypothesismoreimpropable.Ifitshouldhail,theharvestwouldbelost.Theuseofcouldinifclausesindicatestheabilityandpossibility.Ifyoucoulddance,youwouldhavealotmorefun.TYPETHREEWhenweproposeanimpossiblecondition,becauseitreferstothepastanditisthereforenolongerpossible,weusethethirdconditional.Ifyouhadaskedme,Iwouldhavehelpedyou.IfIhadfoundheraddress,Iwouldhavesentheraninvitation.IfJohnhadhadthemoney,hewouldhaveboughtaFerrari.(Sometimeinthepast,Iwantedtosendaninvitationtoafriend.Ididn'tfindheraddress,however.

SointheendIdidn'tsendheraninvitation.)(IknewJohnverywellandIknowthatheneverhadmuchmoney,buthelovedFerraris.He

wouldhavelovedtoownaFerrari,butheneverhadthemoneytobuyone.)Thestructureofthethirdconditionalis:Ifclause:if+pastperfect(had/’d/hadn’t+pastparticiple)Mainclause:would/’d/wouldn’thave+pastparticipleIfyouhadcometotheconcertwithus,Youwouldcertainlyhaveenjoyedit.IfIhadseenyou,ofcourseIwouldhavesaidhello.IfIhadn’tbeensotired,Iwouldhavegoneout.Theothermodalsmight,shouldorcouldcanalsobeenfoundinthethirdconditional.Youmighthavesucceededifyouhadtriedhardenough.IfIhadtakenmyracketwithme,Icouldhaveplayedtenniswithyou.

Now,let’stakealookatthesummaryofthedifferenttypesofconditionalinthetable: