高一英语Unit19 Modernagriculture

高一英语Unit19ModernagricultureⅠ.TeachingGoals:1.Talkaboutmodernagricultureandtheeffectsithasonpeople'slife.2.Practisegivingadviceandmakingdecisions.3.Use“It”foremphasis.4.Readstatisticalgraphs.5.Writeaplanforavegetablegarden.Ⅱ.TeachingTime:FiveperiodsⅢ.BackgroundInformation:1.AnAmericanSmallFarmLastyear,atharvesttime,wevisitedtheSteenhoekfarm,whichis2200mu,or340acres.Typicalfamilyfarmsarerunentirelybyfamilymembers,witheverymemberplayingavitalpartintheoperation.BothofthesefamiliesaredescendantsofDutchimmigrantswhosettledhereoveracenturyago.TheSteenhoekfarmsupports3generations.ThefamilyofMr.andMrs.Steenhoekincludesthreechildrenand2grandchildren.Aswewillsee,thisfamilyisanexcellentexampleofhardworking,experiencedfarmerswhostayonthelandnotpurelybecauseofprofit,butbecausetheyarelivingalife-stylethatsatisfiesthem.SixtypercentoftheSteenhoek'sacresaredevotedtopastureland,onwhichtheyraise120beefcattle.Therestofthelandisusedforgrowingcorn.Fifteenyearsago,theAmericanfarmeconomywasbooming.Farmerscouldspecialize,raisingonecrop,oronetypeofanimal.Today,withanuncertainfarmeconomy,suchanideaisconsideredfoolhardy,anddiversifyingisonewaythatfarmerscanlessontheirriskofloss.Forexample,ifweatheraffectsthesizeofacrop,thesaleofthelivestockwillmakeupthedifference.Iftheanimalsareplaguedbydisease,atleastthereisgraintotaketomarket.KendallSteenhoek,Simon'seldestson,divideshistimebetweenrunningthismachineshopandfarmingzooacresofcorn.HeattendedacommunitycollegeinIowafortwoyearstostudydieselmechanics.Thenheopenedthisrepairshopforfarmmachinery.Kendallalsoplantsandharvestsover30000bushelsofcorneachyear,butitistheincomefromtherepairshopthathasenabledhimtostaywithinthefarmingcommunity.Theheavyequipmentusedonthefarmstodayisinconstantneedofmaintenance,andrequiresprecisiontoolingforrepairs.Byfar,themostimpressiveandcertainlythemostcostlypieceoffarmequipmentusedonasmallfarmisaharvestingmachinecalledacombine,whichcancostupto$100000.ThistypeofmachineryiswhatmakestheAmericanfarmsoefficient.Withacombine,onemanandhisfamilycanharvestanentirecropofa500acrefarmintwoweeks.Thevalueofthecombineisthatitperformsseveralfunctions.Asitmovesthroughafieldofcorn,thissophisticatedmachinecutsthestalk,pluckstheear,discardsthestalk,shucksthecornkernelsofftheearanddepositesthekernelsinastoragebinintheback.Then,aspinningdeviceintherearofthecombineshredsthehusksandshaftsandscattersthemacrossthefield,toserveasmulch,cuttingdownonthepossibilityofsoilerosionfromwinterrains.ThemachineisevenmoreamazingwhenyouthinkthatithasbeeninuseonAmericanfarmsforonlyonegeneration.2.GenesEverylivingcellcontainsgenes.Theyaretoosmalltobeseeninamicroscope,buttheyarevitallyimportant.Eachsetofgenesinthebodycontainsalltheinstructionsneededtomakeahumanbeing.Somegenesdeterminehaircolor.Somedeterminetheshapeofanose.Somegeneshelpdetermineyourheightandevenyourweight.GenesaremadeofachemicalcalledDNA—thelettersstandfordeoxyribonucleicacid(脱氧核糖核酸).Intheearly1950's,twoscientists,FrancisCrickandJamesWatson,figuredouthowthepartsofDNAfittogether.Oncescientistsunderstoodthisstructure,itbecamepossibletotakepiecesofDNAapartandputthemtogetherinnewways.Newkindsofgenescouldbemadeinthismanner.Scientistshavestudiedthegenesofmanyplantsandanimals.Theyhaveworkedoutwhichgenesaffectthecolorofatomatoandthesticknessofitsskin.Workingoutwhichgenesdeterminewhichfeaturesiscalledgeneticmapping,scientistshavebeguntheHumanGenomeProject,anambitiousefforttomapallthegenesinthehumanbody.Somegenesmaybeeffective.Forexample,somethingmightbewrongwiththegenethatmakesbloodclot(凝聚).Anindividualbornwiththisdefectivegenecouldsufferserioushemorrhages(出血)orevenbleedtodeathbecausehisorherbloodfailstoclot.Ifscientistseverlearnhowtomapallthegenesinourbodies,theycoulddeterminewhetherornotanunbornchildhasanydefectivegenes.Theymightevendiscoverhowtotreatthesegenesbeforethechildisborn.TheFirstPeriodTeachingAims:1.Improvethestudents'speakingabilitybypractisinggivingadviceandmakingdecisions.2.Enablethestudentstomastertheexpressionsofgivingadviceandmakingdecisions.3.Getthestudentstolearnmoreaboutagriculture.TeachingImportantPoints:1.Howtoexpressoneself,usingwhatislearnedorgiven.2.Howtoadvisesb.todosomethingandhowtomakedecisions.TeachingDifficultPoints:1.Theusageofsomeexpressions.2.Howtoimprovethestudents'listeningability.TeachingMethods:1.Listeningsomematerialstoimprovethestudents'listeningability.2.Discussiontoletthestudentsexpressthemselvesfreely.3.Groupworkorpairworktogiveeverystudentachancetoexpressthemselves.TeachingAids:1.ataperecorder2.aprojectorandsomeslides3.acomputerTeachingProcedures:stepⅠ.GreetingsandRevisionT:Goodmorning,everyone.Ss:Goodmorning,teacher.T:Sitdown,please.Inthisclass,I'llcheckyourhomeworkfirst,WangPing,readyourhomeworktous,…(Theteacherchecksthestudents'homeworkandhaveadiscussionwiththestudentsaboutthemistakeWangPingmade.Letthestudentshaveaclearunderstandingandcorrectit.)stepⅡ.PreparationforlisteningandspeakingT:Today,we'regoingtolearnanewunit,Unit19,ModernAgriculture(Teacherwritesthefollowingontheblackboard:Unit19Modernagriculture,th