高一Unit 19 Modern agriculture教案.docx

高一Unit 19 Modern agriculture教案.docx

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高一Unit19Modernagriculture教案

Unit19　Modernagriculture

Ⅰ.TeachingGoals:

1.Talkaboutmodernagricultureandtheeffectsithasonpeople'slife.

2.Practisegivingadviceandmakingdecisions.

3.Use“It”foremphasis.

4.Readstatisticalgraphs.

5.Writeaplanforavegetablegarden.

Ⅱ.TeachingTime:

Fiveperiods

Ⅲ.BackgroundInformation:

1.AnAmericanSmallFarm

Lastyear,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.Genes

Everylivingcellcontainsgenes.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.

TheFirstPeriod

TeachingAims:

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.ataperecorder

2.aprojectorandsomeslides

3.acomputer

TeachingProcedures:

stepⅠ.GreetingsandRevision

T:

Goodmorning,everyone.

Ss:

Goodmorning,teacher.

T:

Sitdown,please.Inthisclass,I'llcheckyourhomeworkfirst,WangPing,readyourhomeworktous,…

（Theteacherchecksthestudents'homeworkandhaveadiscussionwiththestudentsaboutthemistakeWangPingmade.Letthestudentshaveaclearunderstandingandcorrectit.）

stepⅡ.Preparationforlisteningandspeaking

T:

Today,we'regoingtolearnanewunit,Unit19,ModernAgriculture（Teacherwritesthefollowingontheblackboard:

Unit19Modernagriculture,theFirstPeriod）.First,let'slearnthenewwordsofthisperiod.Lookatthescreen:

Newwords:

producen.产量、产物、农产品

effectn.结果、影响、作用

diken.堤坝；排水沟

droughtn.干旱

leadern.领导者　

leadv.领导、带领

canen.细长的茎、藤条

sugar-canen.甘蔗

tobaccon.（烟草）制品；抽烟

localadj.地方的、当地的

（Teacherasksonestudenttoreadthenewwords,thencorrectsthemistakesthestudentmade.）

StepⅢ.Warmingup

T:

PleaseturntoPage32.Let'sdoWarmingup.（TeachershowsthegraphsonPage32onthescreen.）LookatthetwographsanddiscussthequestionsonPage32.Youcandoitinpairsorgroups.Inafewminutes,I'llasksomestudentstotalkaboutthem.（Studentsbegintodiscussthequestions.Andteachergoesandjoinsthem.Afewminuteslater,teachersaysthefollowing.）

T:

Areyouready?

Whocangiveusatalkaboutthefirsttopic?

SA,howarepeople'seatinghabbitschangingovertheyears?

SA:

Fromthefirstgraph,wecanseethattheeatinghabitsofthepeopleinourcountryhavechangedgreatly.Before1949,theyhadnotenoughtoeatandoftenwenthungry.Oncenaturaldisastershappened,agreatnumberofpeoplewoulddieofhunger.Beforethereformingandopeningtotheworld,grainwasstillabigproblem.Peoplemainlylivedoncornandfewkindsofvegetables.Sincethe1980s,especiallythe1990s,people'seatinghabitshavegreatlyimproved.Peoplecaneatwhatevertheywant.Moreandmorepeopleeatlessgrain,moremeatandeggsandsoon.Moreandmorepeopleturntheireyestomeat,eggs,milkandallkindsofgreenvegetables.

T:

Whydoyouthinkthishappens,SB?

SB:

ItisallbecauseoftheParty'sgoodpolicies.

T:

Verygood.Itistrueandeveryonecanseethat.Howhasagriculturalproducechangedduringthefirsthalfofthe1990s?

Andwhatdoyouthinkcausedthesechanges?

SC:

Fromthefirsthalfofthe1990s,scientistsstartedtodevelopnewtechniquestoincreaseagriculturalproductionwithoutcausingdamagetotheenvironment.Especiallythenewtechnique,“GM”,hasmadeagriculturalproductionincreasecontinuously.Scientistsdevelopnewkindsofseeds,bettercows,pigs,sheepaswellasfish.Itisthenewtechniquesthatmakeallthispossible.

T:

Doyouagreewithhim,SD?

SD:

Yes,Ido.AndIwanttogiveananswertothethreequestion.

T:

Good,pleasesaythat.

SD:

Withthechangesinpeople'seatinghabits,agricultureaswellasnaturewillhavetochange,too.Peopleareeatingmoremeatandmilk.Thatistosay,theyneedmorefish,pigs,sheepandcattleaswellaspoultry.Tofeedtheseanimals,weneedmoregrain,especiallymoregrass.Toprotectourenvironment,thewaystoraiseanimalshavechanged.Withthedevelopmentofmodernscienceandtechniques,someofthefieldsarenotneededtoproducemorefood.Wecangrowgrass,flowersetc.onthem.Lessfarmersareneededandtheycandootherkindsofwork.

StepⅣ.Listening

T:

Somuchforthediscussion.Nextwe'lldolistening.Thepassageyou'lllistentoisaboutfarming.Ittellsusaboutfarmingofallcountriesinearlytimesandprotectionofnatureandenvironment.Listentothetapecarefullyanddotheexercisesconcerned.Now,readtherequirements,please.（Studentsreadtherequirements.）Nowdoyouknowwhatyou'llhavetodoafterlisteningtothepassage?

（Ss:

Yes.）Duringlistening,I'llplaythetapethreetimes.Afterlisteningforthefirsttime,youcanleaveovertheonesyouarenotsureabout.YoucandothemwhenIplaythetapeforthesecondorthethirdtime.Checkyouranswerswithyourpartnerafterlistening.Areyouclear?

（Ss:

Yes.）（Atlast,teachershowstheanswersonthescreen.）

StepⅤ.Speaking

T:

Nowlet'sdospeaking.Thispartsaysthatagroupoffarmersinyourareahavebeengivenalargepieceofland.Thevillagerstogetherwiththevillageleaderhavetodecidehowtousetheland.Workingroupsoffivestudents.Eachgroupmemberwillplayoneoftheroles.Preparerolecards,discusstheproblemandtrytomakeadecision.Beforediscussion,whocangiveussomeusefulexpressionsaboutgivingadvi