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1、英语:Unit4《GlobalWarming》教案-reading(新人教版选修6)Period2Pre-reading,Reading,ComprehendingTeachingGoals:1.Toreadaboutglobalwarming.2.Togetsomeideaabouttheeffectofglobalwarming.3.Todevelopsomebasicreadingskills.TeachingProcedures:Step1.WarmingUpPurpose:ToarouseSsinterestin
2、learningaboutglobalwarming.1.TeamworkAnswerthequestionsbelow:(1)Haveyoueverseenagreenhouse?(2)Howdoesagreenhousework?(3)Whatdoyouthinkgreenhousegasesdo?2.GroupworkLookatthepicture,andaskSssomequestions.T:Whatisthisbuildingmadeof?S1:It’smadeofplastic.T:What’sitspur
3、pose?S2:Plantscangrowinitwhenit’scoldoutside.T:Howdoesitwork?S3:Theglasstrapstheheatfromthesun,makingtheairwarmsothatplantsgrowbetter.Step2.Pre-readingPurpose:TogetSstolearnaboutgreenhousegases.1.GroupworkNowlookattheword“GREENHOUSEGASES”.Whatdoesitmean?Greenhouse
4、gases(GHG)aregaseouscomponentsoftheatmospherethatcontributetothegreenhouseeffect.Themajornaturalgreenhousegasesarewatervapor,whichcausesabout36-70%ofthegreenhouseeffectonEarth(notincludingclouds):carbondioxide,whichcausesbetween9-26%;andozone,whichcauses老榆木家具www.y
5、umu365.com老榆木家具ovuiesd4between3-7%(notethatitisnotreallypossibletoassertthatsuch-and-suchagascausesacertainpercentageoftheGHE,becausetheinfluencesofthevariousgasesarenotadditive.Thehigherendsoftherangesquotedareforthegasalone;thelowerend,forthegascountingoverlaps)
6、.Naturallyoccurringgreenhousegasesincludewatervapor,carbondioxide,methane,nitrousoxide,andozone.Certainhumanactivities,however,addtothelevelsofmostofthesenaturallyoccurringgases.Verypowerfulgreenhousegasesthatarenotnaturallyoccurringincludehydrofluorocarbons(HFCs)
7、,perfluorocarbons(PFCs),andsulfurhexafluoride(SF6),whicharegeneratedinavarietyofindustrialprocesses.Eachgreenhousegasdiffersinitsabilitytoabsorbheatintheatmosphere.HFCsandPFCsarethemostheat-absorbent.2.IndividualworkGetSstoanswerthesequestionsindividually.Thenlett
8、hemdiscusstheanswers.(1)Whowrotethemagazinearticle?Whatisthenameofthemagazine?(2)Whatarethenamesofthethreescientistsmentionedinthearticle?(3)Whatdotheyt