必修4Unit 2 Chemical or Organic Farming公开课优质获奖课件优质PPT.pptx
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Theyneed,+,+,+,Fertilizers?
Chemicalfertilizers,Naturalfertilizers,chemicalfarming,organicfarming,Predictwhatwewillknowfromthepassage.Wellknow.,ChCemheimcaiclaolorrOOrrggaanniiccFFaarrmmining?
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Task1Underlinethetopicsentenceofeachparagraph.,AWhataresomeoftheproblemscausedbychemicalfertilizers?
First,theydamagethelandbykillingthehelpfulbacteriaandpestsaswellastheharmfulones.Chemicalsalsostayinthegroundandundergroundwaterforalongtime.Thisaffectscropsand,therefore,animalsandhumans,sincechemicalsgetinsidethecropsandcannotjustbewashedoff.Thesechemicalsinthefoodsupplybuildupinpeoplesbodiesovertime.Manyofthesechemicalscanleadtocancerorotherillnesses.Inaddition,fruit,vegetablesandotherfoodgrownwithchemicalfertilizersusuallygrowtoofasttobefullofmuchnutrition.Theymaylookbeautiful,butinsidethereisusuallymorewaterthanvitaminsandminerals.,Task1Underlinethetopicsentenceofeachparagraph.,A.Whataresomeoftheproblemscausedbychemicalfertilizers?
B.C.D.,Task1Underlinethetopicsentenceofeachparagraph.,BWiththesediscoveries,somefarmersandmanycustomersarebeginningtoturntoorganicfarming.Organicfarmingissimplyfarmingwithoutusinganychemicals.Theyfocusonkeepingtheirsoilrichandfreeofdisease.Ahealthysoilreducesdiseaseandhelpscropsgrowstrongandhealthy.Organicfarmers,therefore,oftenpreferusingnaturalwastefromanimalsasfertilizer.Theyfeelthatthismakesthesoilintheirfieldsricherinmineralsandsomorefertile.Thisalsokeepstheair,soil,waterandcropsfreefromchemicals.,Task1Underlinethetopicsentenceofeachparagraph.,COrganicfarmingalsousemanyothermethodstokeepthesoilfertile.Theyoftenchangethekindofcropineachfieldeveryfewyears,forexample,growingcornorwheatandthenthenextyearpeasorsoybeans.Cropssuchaspeasorsoybeansputimportantmineralsbackintothesoil,makingitreadyforcropssuchaswheatorcornthatneedrichandfertilesoil.Organicfarmersalsoplantcropstousedifferentlevelsofsoil,forexample,plantingpeanutsthatusethegroundssurfacefollowedbyvegetablesthatputdowndeeproots.Someorganicfarmerspreferplantinggrassbetweencropstopreventwindorwaterfromcarryingawaythesoil,andthenleavingitinthegroundtobecomeanaturalfertilizerforthenextyearscrop.Thesemanydifferentorganicfarmingmethodshavethesamegoal:
togrowgoodfoodandavoiddamagingtheenvironmentorpeopleshealth.,Task1Underlinethetopicsentenceofeachparagraph.,DOverthepasthalfcentury,usingchemicalfertilizershasbecomeverycommoninfarming.Manyfarmerswelcomedthemasagreatwaytostopcropdiseaseandincreaseproduction.Recently,however,scientistshavebeenfindingthatlong-termuseofthesefertilizerscancausedamagetothelandand,evenmoredangerous,topeopleshealth.,Thetopicsentencesofeachparagraph:
Whataresomeoftheproblemscausedbychemicalfertilizers?
Withthesediscoveries,somefarmersandmanycustomersarebeginningtoturntoorganicfarming.Organicfarmersalsousemanyothermethodstokeepthesoilfertile.Recently,however,scientistshavebeenfindingthatlong-termuseofthesefertilizerscancausedamagetothelandandevenmoredangerous,topeopleshealth.Task2Putthefourparagraphsinorder.ABCD,Thetopicsentencesofeachparagraph:
Withthesediscoveries,somefarmersandmanycustomersarebeginningtoturntoorganicfarming.Organicfarmersalsousemanyothermethodstokeepthesoilfertile.Recently,however,scientistshavebeenfindingthatlong-termuseofthesefertilizerscancausedamagetothelandandevenmoredangerous,topeopleshealth.Task2Putthefourparagraphsinorder.,B,C,DA,Task2FindthestructureofthepassageWhatsthefunction(功能)ofthefirstparagraph?
toexplainthetopictoanalysethetopictointroducethetopicWhichtwoparagraphscanbegroupedtogether?
Para2problemsPara3organicfarmingPara4organicfarmingmethodsWhatstherelationshipbetweenParagraph2andParagraph3&
4?
Para2Chemicalfarmingcausestheproblems.Para3&
4Organicfarmingsolvestheproblems.,Para1TopicWhyarechemicalfertilizerssopopularinfarming?
.agreatwaytostopcropdiseaseandincreaseproduction.,Para2Problems,1.,2.,Howmanyproblemsarelistedinthisparagraph?
Problemscausedbychemicalfertilizers,First,Also,3.Inaddition,Watercropsanimals,humans,Damagetheland,Fruit,vegetables,otherfood,Para3&
4Solution,Task1Whatdoorganicfarmersfocuson?
Theyfocusonkeepingtheirsoilrichandfreeof,disease.,Para3&
4Solution,Task2Underline,theorganicfarming,methods,andtheir,advantages,inPara3&
4.,Task3Retelltheorganicfarmingmethodswiththehelpofthekeyinfo