安徽省滁州二中高二英语《Unit21HumanBiologyTheSecondPeriodGrammar（Ⅰ）》教案StepⅠRevisionandlead-inT:Attheendoflastperiod,Iaskedyoutofindoutallthesentencesinitalicsinthearticle—SuperAthletes.Haveyoufinishedcollectingthesesentencesinitalics?Howmanysentencesinitalicsarethereinthisarticle?Ss:Therearesevensentencesinitalicsinthisarticle.T:Right.Thenwhowouldliketopresentthesesentences?S:Iwouldliketodoit.ManycontemporaryamateurathleteswouldhavebrokenworldrecordsiftheyhadtakenpartinthefirstOlympicGames.Ifrecordsfall,itisusuallyduetobetterequipment,traininganddiet.BenJohnsonwouldstillbethe100metresworldholderifhehadnotbeencaughttakingdrugsinthe1988Olympics.IfcurrentOlympicchampion,MarionJones,tooksuchdrugs,shewouldprobablyhavebrokenthatworldrecordmorethanonce.Unlesswearecareful,“gene-therapy”willbethenextbigthreat.Ifgene-therapywereusednow,itwouldbealmostimpossibletofindout.Ifagenerationofsportsstarswithenhancedgeneswerecreated,itwouldcontradictthewholespiritofsport.T:Great.Youhavedoneagoodjob.Inthisperiod,studentsareexpectedtoreviewsomeconditionalsentencestheyhavelearnedbefore,andthentheywilllearndifferentusageoftherealandunrealconditionals.Ifstudentswanttoknowmoreabouttheusage,theycanreadthedetailedexplanationthatareincludedintheappendix(附件).Teachersmaydistributethemtostudentsforreference.StepⅡTheconditionalsentencesShowthestudentsthesentencestheypresentaboveonthescreenandhavethemfindoutthedifferencesamongthem.Itaimstohelpthemtotellthedifferencesamongthem.T:Lookatthesefoursentences,whattimedoeseachcondition(underlined)inthesentencereferto:past,presentorfuture?Whattenseisused?Let’scompletethetablebelow.ConditionTimereferenceVerbform1thepresentpastsimple2thepresentpastsimple3thepasthad+pastparticiple4thepasthad+pastparticipleT:Whattimedoestheresultinthesentencesreferto:pastorpresent?Whatverbformisused?ResultTimereferenceVerbform1thepastwould+perfectinfinitive2thepastwould+perfectinfinitive3thepresentwould+verb4thepresentwould+verbTask3ExplanationT:Thisisastructureusedtotalkaboutunreal,imaginaryorcontrarytothefactssituationsinthepresent,inthefutureorinthepast.PleasepayattentiontotheverbformsofeachclauseandmainsentenceandthenIwillexplainhowitisformed,andwhenweuseit.IfclauseMainclauseinthepresentpastsimple(be—were)would(should,could,might)+verbinthefuturepastsimple(be—were)orshould+verborwereto+verbwould(should,could,might)+verbinthepasthad+pastparticiplewould(should,could,might)+havepastparticipleT:Maybeit’shardforustorememberthesesituations,soitneedspractisingrepeatedly.Therearesomesentencesaboutthesesituationsonthescreenforustopractise.Ifweleftnow,weshouldarriveingoodtime.(That’simpossible.)→Wecannotleavenow,sowewillnotarriveingoodtime.Wewouldhavedroppedbyifwehadhadtime.(That’sunreal.)→Becausewedidn’thavetime,wecouldn’tdropby.Ifthehurricanehadhappenedduringthedaytime,therewouldhavebeenmanymoredeaths.(That’sunreal.)→Becausethehurricanehappenedatnight,therewerefewerdeaths.Ifyoulivedthereforawhile,youwouldchangeyourmind.(That’snotgoingtohappen.)→Youdon’tlivethereforawhile,soyouwillnotchangeyourmind.Ifhecametomorrow,wecouldaskhim.(That’snotgoingtohappen.)→Hewillnotcometomorrow,sowecan’taskhim.T:Ifyouneedmoreandfurtherinformation,pleasereadGrammarSummary5,page101.Now,pleaseturntopage35,Ex.7.It’saboutmixedconditionalsentencesinwhichtherearemixedtimereferencebetweenthe“if”clausesandthemainsentences,forexample,thepastconditionalswithpresentconsequences,thepresentconditionalswithpastconsequences,etc.Sampleanswers:StepⅢConsolidationLetthestudentsdothefollowingexercisestopractisewhattheyhavelearnedinthisperiod.Ex.9onpage35.Askthestudentstowriteaboutthreethingsthattheydidordidn’tdo,orthathappenedordidn’thappentotheminthepastandwhatthepresentconsequencesare.Usemixedconditionalsentences.StepⅣHomeworkTounderstandtheconditionalsbetterandusethemcorrectly,studentsshouldbeabletopractisemore.LetthestudentsfinishExx.1-5onpage80,whichwillhelpthemidentifythemixedconditionals.
