2023学年完整版Unit4Globalwarming设计

Unit4GlobalWarming教学设计教学目标Ⅰ.教学内容分析本单元的中心话题是人类当今面对的环境问题，主要探讨了“全球变暖”和“节约能源”等方面的问题。由于人类过多使用不可再生能源，大气中二氧化碳的含量逐年增加，导致全球气温上升。通过学习本单元，让学生了解能源分为“不可再生能源”和“可再生能源”，帮助学生树立“节约能源、保护环境”的主人翁意识。语言知识和语言技能主要围绕“全球变暖”和“节约能源”这一主题设计的。“热身”(Warmingup)部分要求学生列举家中、学校或其他地方使用能源的物体，指出这些能源的来源，并尽可能多地列举不同的能源。能源可分为两类：一类是可再利用能源；另一类是一次性能源。把前面列举的能源按能否再利用这一标准进行分类。本部分提供了六幅图片，教师可以从识图开始组织教学。还可以让学生搜集一些其他相关图片。这六幅图分别为：风力（windpower）、燃煤发电站（acoalpowerstation）、炼油厂（anoilrefinery）、原子能发电站（anuclearpowerplant）、太阳能接受器（solarpanels）、水坝（ahydrodam）。“读前”(Pre-reading)部分首先介绍什么是温室、它有什么作用，然后要求学生讨论大气中温室气体的作用。温室是由玻璃构成的建筑，主要用于花果蔬菜的培植。温室是由玻璃构成的建筑，主要用于花果蔬菜的培植。温室能阻止热量散发，因而能帮助植物度过寒冷的时期。该部分的讨论有利于学生预测课文内容和理解阅读课文中的温室气体效应。“阅读”(Reading)部分是一篇杂志文章，主要讲述了地球温度上升的现象和原因。20世纪中，地球的温度上升了华氏1度。这看上去是一个很小的数字，但相对于自然界的其他现象来说，这个增长速度是迅猛的。这种现象是自然发生的还是人为的？这个问题引起激烈的争论。许多科学家认为，这种变化是人类燃烧矿物燃料所致。这些物质的燃烧产生以二氧化碳为主的温室气体。正因为自然界有温室气体的存在，地球才不至于很冷。但大量排放二氧化碳会使地球普遍升温。对于地球升温，科学家有不同的看法。有些科学家认为，这个问题很严重。地球升温会导致海水上涨、风暴、干旱、饥荒、物种毁灭和疫病等。也有科学家认为，地球升温有利于改善人类生活，比如，庄稼长得更快、产量更高等。文章最后以开放性的问题结尾要求读者思考：对于全球变暖，人类要不要采取措施？“理解”(Comprehending)部分设置了三个活动。阅读课文中的杂志文章，练习1首先就作者、杂志名称、文中提到的科学家、文中出现的曲线图等内容提问，并要求学生概括文章的主题。然后，练习2要求学生细读课文，并判断所给六个句子是否符合课文内容。最后练习3要求学生小组讨论：Weshoulddonothingaboutglobalwarming.在小组讨论的基础上，把全班分成正方和反方，举行一个辩论会。“语言学习”(Learningaboutlanguage)的词汇学习部分共两个练习。练习1让学生重新阅读课文并找出文中一些具有不同词性或不同含义的生词，分辨它们在文中的含义。练习2则要求学生使用前几个部分所学的生词来完成与“全球变暖”话题相关的一些句子。语法学习部分中练习1让学生通过对比课文中it作强调作用的句子与其他句子的区别，发现并熟悉强调句型及其规律。练习2则要求学生针对所给句子的划线部分转换句型，练习使用it的强调句型。练习3则给予学生更广阔的思维空间，让学生根据自己对“全球变暖”话题的认识运用强调句型进行复述或表达自己的观点。“语言运用”(Usinglanguage)部分的“读和写”(Readingandwriting)让学生就WHATCANWEDOABOUTGLOBALWARMING?进行讨论。欧阳光给关爱地球组织杂志写电子邮件，请求帮助。杂志回信指出，群策群力，问题可解。他们提出了几个具体措施：1、减少电器的使用；2、尽量步行或骑自行车；3、回收玻璃、塑料、报纸等物品；4、劝父母购买节能产品；5、植树；6、宣传有关知识。阅读之后，教师可以让学生就文中提出的建议进行讨论，并可以让学生提出更多的建议。这样，学生就有了充分的材料去完成写的任务：设计一个海报，介绍减少空气中二氧化碳含量的方法。听力部分是大学生李斌与陈教授的一段对话，讨论能源的使用问题，并学习表达“赞成”或“不赞成”的交际用语。“小结”(Summingup)部分要求学生就全球变暖、如何减少二氧化碳、强调句、相关词语等方面进行自我评价，判定学习情况：了解还要进一步改进的地方。“学习建议”(Learningtip)部分介绍首字母大写的规则，要求学生在阅读中学会辨别人名、地名、书名、题目等。Ⅱ.教学重点和难点1.教学重点：(1)本单元的生词和短语。(2)it的用法。(3)了解“全球变暖”、“能源的种类”和“节约能源”等方面的知识。帮助学生树立“节约能源、保护环境”的主人翁意识。2.教学难点(1)学会表达同意和不同意、责备和抱怨等日常交际用语。(2)学习it在强调句中的用法。(3)学习如何写一幅表达自己观点、劝说他人节约能源、保护环境的海报。(4)学习有关气候、能源、环保的词汇。Ⅲ、教学课时计划本单元用五课时：第一课时：WarmingUp第二课时：Pre-reading,Reading,Comprehending第三课时：LearningaboutLanguage第四课时：UsingLanguage第五课时：Summingup-Learning-TipⅣ、教学步骤：Period1WarmingUpTeachingGoals:1.ToarouseSs’interestinlearningaboutglobalwarming.2.TogetSstoknowtheenergysource.Teachingprocedures:Step1.Leading-inPurpose:ToactivateSsandarousethemtotalkaboutglobalwarming.T:Hello,everyone.Todaywearegoingtoreadaboutglobalwarming.Butfirstlet’sthinkaboutwhatmovestheworldaround.Yes,itisenergy.Butwhatisenergy?Energyisafundamentalquantitythateveryphysicalsystempossesses;itallowsustopredicthowmuchworkthesystemcouldbemadetodo,orhowmuchheatitcanproduceorabsorb.Inthepast,energywasdiscussedintermsofeasilyobservableeffectsithasonthepropertiesofobjectsorchangesinstateofvarioussystems.Basically,ifsomethingchanges,somesortofenergywasinvolvedinthatchange.Renewableenergysourceslikewindpowerdon’temitcarbondioxide.Step2WarmingupPurpose:ToleadSstothetopicofthisunit.PairworkGetSstoaskeachotherthefollowingquestions,andthenaskthemtopresentitbeforetheclass.(1)Whatisenergy?(2)Wheredoesitcomefrom?(3)Whatenergysourcesarerenewable?(4)Whatenergysourcesarenon-renewable?2.Groupwork(1)GetSstotalkaboutsourcesofenergyaccordingtothefollowingphotos.TheabovepicturescanbeusedforSstotalkabout,andSscanalsotalkasmuchastheycan.BylearningWarmingUpweallknowthatenergyissoimportant,butwheredoesitcomefrom?Therearedifferentformsofenergy:Lightenergy 光能 Heatenergy 热能Soundenergy 声能 Chemicalenergysource 化学能源Nuclearenergy 核能 Internalenergy 内能Kineticenergy 动能 Potentialenergy 势能能源类型定义实例一次能源直接来自自然界而未经加工转换的能源化石燃料、太阳能、核能、生物燃料、水能等二次能源由一次能源直接或间接转化而来的能源电能、煤气、汽油、沼气、氢能等可再生能源不随其本身的转化或被人类利用而减少的能源太阳能、生物能、水能、风能、地热能等非再生能源随其本身的转化或被人类利用而减少的能源化石燃料、核燃料(2)ConclusionWhenenergychangesfromoneformtoanother,theamountofenergystaysthesame.Energycannotbemadeordestroyed.Thisfactiscalled“conservationofenergy”.Mattercanbemadeintoenergythroughprocesseslikenuclearfissionandnuclearfusion.3.Competition:TakethequizbelowandseewhetherSscanfillintheblanks.ThingsthatuseenergySourcesofenergyRenewable/non-renewablelightsheatingtelevisioncassetteplayervideorecordercomputerfridgestovewashingmachinehairdryercoal(1)______________oil(2)______________naturalgas(3)______________wind(windpower)(4)_______________sun(solarenergy)(5)________________uranium(nuclearenergy)(6)________________water(hydro-electricpower)(7)________________plantwaste(biomassenergy)(8)________________hotspringsorgeysers(geothermalenergy)(9)_______________thesea(tidalenergy)(10)____________SuggestedAnswers:(1)non-renewable;(2)non-renewable;(3)non-renewable;(4)renewable;(5)renewable(6)non-renewable;(7)renewable;(8)renewable;(9)renewable;(10)renewable4.HomeworkWriteashortcompositionaboutsourcesofenergy.Period2Pre-reading,Reading,ComprehendingTeachingGoals:readaboutglobalwarming.getsomeideaabouttheeffectofglobalwarming.developsomebasicreadingskills.TeachingProcedures:Step1.WarmingUpPurpose:ToarouseSsinterestinlearningaboutglobalwarming.1.TeamworkAnswerthequestionsbelow:(1)Haveyoueverseenagreenhouse?(2)Howdoesagreenhousework?(3)Whatdoyouthinkgreenhousegasesdo?2.GroupworkLookatthepicture,andaskSssomequestions.T:Whatisthisbuildingmadeof?S1:It’smadeofplastic.T:What’sitspurpose?S2:Plantscangrowinitwhenit’scoldoutside.T:Howdoesitwork?S3:Theglasstrapstheheatfromthesun,makingtheairwarmsothatplantsgrowbetter.Step2.Pre-readingPurpose:TogetSstolearnaboutgreenhousegases.1.GroupworkNowlookattheword“GREENHOUSEGASES”.Whatdoesitmean?Greenhousegases(GHG)aregaseouscomponentsoftheatmospherethatcontributetothegreenhouseeffect.Themajornaturalgreenhousegasesarewatervapor,whichcausesabout36-70%ofthegreenhouseeffectonEarth(notincludingclouds):carbondioxide,whichcausesbetween9-26%;andozone,whichcausesbetween3-7%(notethatitisnotreallypossibletoassertthatsuch-and-suchagascausesacertainpercentageoftheGHE,becausetheinfluencesofthevariousgasesarenotadditive.Thehigherendsoftherangesquotedareforthegasalone;thelowerend,forthegascountingoverlaps).Naturallyoccurringgreenhousegasesincludewatervapor,carbondioxide,methane,nitrousoxide,andozone.Certainhumanactivities,however,addtothelevelsofmostofthesenaturallyoccurringgases.Verypowerfulgreenhousegasesthatarenotnaturallyoccurringincludehydrofluorocarbons(HFCs),perfluorocarbons(PFCs),andsulfurhexafluoride(SF6),whicharegeneratedinavarietyofindustrialprocesses.Eachgreenhousegasdiffersinitsabilitytoabsorbheatintheatmosphere.HFCsandPFCsarethemostheat-absorbent.2.IndividualworkGetSstoanswerthesequestionsindividually.Thenletthemdiscusstheanswers.(1)Whowrotethemagazinearticle?Whatisthenameofthemagazine?(2)Whatarethenamesofthethreescientistsmentionedinthearticle?(3)Whatdotheythinkaboutglobalwarming?Dotheyagreewithoneanother?(4)Whatarethetwographsabout?(5)Whatisthemaintopicofthearticle?Step3.Reading1.SkimmingPurpose:Togetabriefunderstandingofthetext.Readthroughthetext,preferablythefirstandthelastsentencesofeachparagraphandwritethekeysentenceofeachparagraph.Keysentencesofeachparagraph:(1)Adebateoverwhetheritishumanactivitythathascausedtheglobalwarmingorwhetheritisjustanaturalphenomenon.(2)Manyscientistsbelievepeoplehavecausedtheincreaseintheearth’stemperature.(3)Theincreasedextraamountofcarbondioxidetrapsmoreheatenergycausingtheglobaltemperaturetogoup.(4)Thelevelsofcarbondioxidehaveincreasedgreatlyoverthelast100to150years.(5)Therearesomedifferentattitudestowardsthecausesofthisincreaseincarbondioxide.(6)Overthenext100yearstheamountofwarmingcouldbeaslowas1todegreesCelsiusbutitcouldbeasmuchas5degreesCelsius.(7)Anincreaseoffivedegreeswouldbeacatastrophe.(8)Futurewarmingwouldcausethesealeveltorisebyseveralmeters.(9)Somepredictanywarmingwillbemildwithfewbadenvironmentalconsequences.(10)Morecarbondioxideisapositivething.(11)Nooneknowswhattheeffectsofglobalwarmingwillbe.2.ScanningPurpose:TogetSstohavesomedetailsinthetext.Readthearticlecarefully.Arethesestatementstrueorfalse?WriteaTforeachtruesentenceandanFforeachfalsesentence.(1)Thetemperaturelastcenturydidn’tincreasemuch.()(2)Everyonebelievesthatglobalwarmingiscausedbytheactivitiesofhumans.()(3)JaniceFosterbelievesthatburningfossilfuelscausesglobalwarming.()(4)Naturalgasisagreenhousegas.()(5)Carbondioxideisabyproductofburningfossilfuels.()(6)PeopleacceptCharlesKeeling’sdatabecausehetookaccuratemeasurements.()(7)Floodingcouldbeoneoftheeffectsoffutureglobalwarming.()(8)GeorgeHambleybelievesscientistsarejustguessingabouttheeffectsofglobalwarming.()(9)GerogeHambleyisworriedabouttheeffectsofcarbondioxideonplantgrowth.()(10)Itisclearwhattheeffectsofglobalwarmingwillbe.()SuggestedAnswers:(1)F (2)F(3)T(4)F(5)T(6)T(7)T(8)T(9)F(10)F3.ListeningPurpose:TotrainSslisteningability.Listentothetapeandfollowitinalowvoice.4.GroupworkSsaredividedintofourgroups.Eachgroupissupposedtoreadthrougheachpartandthendiscussthem.Part1(Paragraph1)compare比较●常见用法：①compare…with…把…和…比较Comparedwithhim,Iamfast.②compare…to…把…比作…Lifeisoftencomparedtovoyage.(2)comeabout发生Howdiditcomeabout?那事是怎么发生的?●常见词组：comeacross 偶遇；碰到 comeround 恢复知觉，comealong 进展；进行 cometo 涉及；到达；共计comeout 公开；问世；出版 cometooneself 恢复知觉comeupwith 想出(4)phenomenonn现象Itisonlyasocialphenomenon,butnotaphenomenonofnature.Part2(Paragraph2,3,4)fueln燃料Don’tleavetheengineswitchedon.Itwastesfuel.●拓展：fuelv加油；补给燃料Thecarisbeingfuelledreadytotrytobeatthespeedrecord.(2)quantitiesof大量Largequantitiesofmoneyhavebeenspentonthebridge.●拓展：alargequantityof大量的Heatealargequantityofnice.(3)perprep每;每一Thefruitcosts30penceperkilo.Howmuchdoyouearnperweek?Part3(Paragraph5,6,7,8,9)(1)datan资料;数据Wehaven’tgotenoughdata..(2)resultin导致Theaccidentresultedinthedeathoftwopassengers.Itresultedinsuccess.●拓展：resultfrom由于Hisillnessresultedfromeatingbadfood.(3)catastrophen突如其来的大灾难；大灾祸Thewarwasaterriblecatastropheinwhichmanypeopledied.(4)climaten气候Wehaveamildclimatehere.(5)consequencen结果；后果；影响Asaconsequenceofbeinginhospital,Shellydecidedthatshewantedtobecomeanurse.●常见词组：inconsequence因此，由此inconsequenceof…由于…的缘故(6)statevt陈述；说明Thebusmenhavestatedthatthestrikewillcontinueuntilgeneralagreementisreachedaboutpayandworkingconditions.(7)range n&v①种类；范围；幅度Thereisawiderangeoftemperature.气温变化很大。②vi(在一定范围内)变化Thenumberrangesbetween5and15.③vt排列，整理Pleaserangethegoodsneatlyintheshopwindow.Part4(Paragraph10)(1)buildup逐步建立；增加；增进Weneedtobuildupourreputation.Trafficisbuildinguponroadsintothecity.(2)Keepon继续Pricekeptonincreasing.Hedidn’tstoprunning;hejustkepton.●拓展：keepondoing与keepdoing的区别：keepondoing表示动作反复发生；keepdoing表示状态或动作的持续。Hekeptonstandingupinclass.他在课堂上一再地站起来。Hekeptstandingthereforhalfanhourwithoutmoving.他一动不动地在那里站了半个小时。Step4.Post-readingPurpose:Tohaveadeepunderstandingofthetext.1.GroupworkNowyouaregoingtodiscussthestatement:Weshoulddonothingaboutglobalwarming.Followtheseinstructions:Getintogroupsofsix.Decidewhichthreeinyourgrouparegoingtoagreewiththestatement(GroupA)andwhichthreearegoingtodisagreewiththestatement(GroupB).(2)GroupAstudentsdiscusswhytheyagreewiththestatement;GroupBstudentsdiscusswhytheydisagree.(3)GroupsAandBgettogether.Theytelleachotherthereasonsforagreeingordisagreeingwiththestatement.2.IndividualworkAskSstoanswerthefollowingquestions.Presenttheiropinionstootherclassmates.(1)Whatdoyouthinkofglobalwarming?(2)Doyouthinkitserious?3.Discussion(1)Globalwarmingreferstoanaverageincreaseintheearth’stemperature,whichinturncauseschangesinclimate.(2)Earth’sclimatehasbeenchangingconstantlyoverits5-billion-yearhistory.(3)Theearthcouldbegettingwarmeronitsown.(4)Scientistsaresureaboutthegreenhouseeffect.TheyknowthatgreenhousegasesmaketheEarthwarmerbytrappingenergyintheatmosphere.(5)Withoutthegreenhouseeffect,theearthwouldnotbewarmenoughforhumanstolive.(6)Awarmerearthmayleadtochangesinrainfallpatterns,ariseinsealevel,andawiderangeofimpactsonplants,wildlife,andhumans.(7)Scientistsdon’tknowexactlywhatwillhappeninthefuture.Buttheycanusespecialcomputerprogramstofindouthowtheclimatemaychangeintheyearsahead.(8)Globalwarmingmaybeabigproblem,buttherearemanylittlethingswecandotomakeadifference.Step5.ReflectivethinkingFirstshowthefollowingquestionstoSsandthenaskSstodiscussthemingroups.1.Whatdoyouthinkcauseglobalwarming?2.Howdoesglobalwarmingaffectyouandothers?3.Howdoesglobalwarmingaffectthenature?4.Whendoyousendgasesintotheair,whichaffecttheearth?(Usetheairconditioner,rideinacar,anduseafridge…)Step6.Homeworkthenewwordsandexpressionstomakesomesentences.towriteashortcomposition.Thetitleis“Howtoslowclimatechange”,beginningwith“Globalwarmingdoesnothavetooccur.Itispossibleforthehumanracetoslowdownglobalwarmingandmaybeevenremovealloftheeffectthatpeoplehaveontheclimate.”Period3LearningaboutLanguageTeachingGoals:enableSstomastersomeusefulwordsandexpressions.discoverusefulstructures.getSstohaveknowledgeofthegrammarpoint:theuseofit.TeachingProcedures:Step1.FreetalkGetSstotalkaboutwhatcausesglobalwarming.Step2.WordstudyPurpose:Toconsolidatethewordsandphrasesinthetext.1.IndividualworkGooverthenewwordsandphrasesintheprevioussections.Thencompleteeachsentencewithoneofthosenewwordsorphrases.(1)CharlesKeelingcollectedonthecarbondioxidecontentintheatmosphereoveraforty-yearperiod.Hefoundthattheamountofcarbondioxide_________increasingduringthattime.(2)Althoughweareburningcoalinhugeeveryyear,wewon’tofitforcenturies.(3)Iftheamountofgreenhousegasescontinuestowecouldbefacingaglobal.(4)Manyscientistsbelievethatglobalwarminghasthroughtheburningoffossilfuels.Theydonotthinkthatignoringtheissueisworththe_______.(5)describesweatherconditionsoveraperiodofyearsinaparticularplace.(6)Theofarisingsealevelwouldbewidespreadflooding.(7)TheuseofenergyinSusanna’scountryislowtheuseofenergyintheUSA.(8)Thewarmingoftheearthisathatcausegreatconcern.(9)Theshowstemperaturechangesduringthe20thcentury.(10)Onehectareofforestcanabsorb23tonsofcarbondioxideyear.SuggestedAnswers:data,kepton(2)quantities,runout(3)buildup,catastrophe(4)comeabout,risk(5)Climate(6)consequence(7)comparedto(8)phenomenon(9)graph(10)per2.PairworkLookatthetwographsonpage26.Thencompletetheparagraphsaboutthemwithappropriatewords.Dotheexerciseinpairs.Thefirstgraphshowstheglobalbetweenand.ThetemperatureanddecreasedoverthisperiodbutonthewholeitbyaroundonedegreeFahrenheit.Duringthistime,theearthreacheditstemperatureinaboutanditshighestinwasasteadyinthetemperatureduringthetwentyyearsaftercanseefromthegraphthattheearthhasbecomesinceearlylastcentury.Thesecondgraphshowstheamountofintheatmospherefromto.Thecarbondioxidesteadilyoverthisforty-yearperiod.Itwentupfrom315to370partsmillion.SuggestedAnswers:temperature;1860,2000;increased/rose/wentup;increased/rose/wentup;coolest/lowest;1910;increase/rise;warmer;carbondioxide;1957;1997;content;increased/rose/wentup;perStep3.Grammar1.It构成的英语强调结构①强调句型的基本结构形式为：“Itis/was+被强调部分+that+句子的其余部分”当被强调部分是人时that也可以换成who。如：ProfessorLiuteachesusEnglishthisyear.今年刘教授教我们英语。ItisprofessorLiuwho/thatteachesusEnglishthisyear.(强调主语)ItisEnglishthatProfessorLiuteachesusthisyear.(强调宾语)ItwasthisyearthatProfessorLiuteachesusEnglish.（强调状语）②强调句型的一般疑问句式：Is/Wasit+被强调部分+that+句子的其余部分？IsitProfessorLiuwho/thatteachesusEnglishthisyear?③强调句型的特殊疑问句式：特殊疑问句+is/wasit+被强调部分+that+句子的其余部分？WhoisitthatteachesusEnglishthisyear?WhatsitthatProfessorLiuteachesusthisyear?2.强调句型的特点去掉Itis(was)及that(who)后，在不添词、不减词的前提下能重新构成一个意义完整的句子。这也是判断一个句子是否是强调句型的依据。3.强调句型的时态如果原句中谓语动词使用的是现在或将来时间范畴的时态（一般现在时、现在进行时、现在完成/现在完成进行时、一般将来时、将来进行时、将来完成时等），用Itis…that…。如果原句中谓语动词为过去时间范畴的时态（一般过去时、过去进行时、过去完成时、过去将来时等），则用Itwas…that…。4.not…until句型的强调句型当被强调的是not…until句型时，应将not置于until之前，主句由否定句改为肯定句。如：Hedidn’tleaveuntil11o’clock.他直到11点才离开。Itwasnotuntil11o’clockthatheleft.（强调notuntil时间状语）5.Practice(1)Itwasn’tuntilnearlyamonthlaterIreceivedthemanager’sreply.A.since B.when C.as D.that(2)Itwasbackhomeaftertheexperiment.A.notuntilmidnightdidhego B.untilmidnightthathedidn’tgoC.notuntilmidnightthathewent D.untilmidnightwhenhedidn’tgo(3)Why!Ihavenothingtoconfess.youwantmetosay?A.Whatisitthat B.Whatitisthat C.Howisitthat D.Howitisthat(4)Itisthesepoisonousproductscancausethesymptoms(症状)oftheflu,suchasheadacheandachingmuscles.A.who B.that C.how D.what(5)Itwasbecauseofbadweatherthefootballmatchhadtobeputoff.A.so B.sothat C.why D.that(6)ItwasforthisreasonherunclemovedoutofNewYorkandsettleddowninasmallvillage.A.which B.why C.that D.how(7)Itistheabilitytodothejobmatternotwhereyoucomefromorwhatyouare.A.it B.that C.one D.this(8)Itwashowtheyoungmanhadlearnedfiveforeignlanguagesattractedtheaudience’sinterest.A.sothat B.that C.what D.inwhich(9)Itwashesaiddisappointedme.A.what;that B.that;that C.what;what D.that;what(10)Itwasnotuntil1920regularradiobroadcastsbegan.A.while B.which C.that D.sinceSuggestedAnswers:(1)～(5)DCABD(6)～(10)CBBACStep4.HomeworkRewriteeachsentencewith“Itis…that…”togivemoreemphasistotheunderlinedpart.1.Greenhousegaseshavewarmedtheearthbytrappingheatenergyintheatmosphere.2.Thegreenhouseeffectgivestheearth’ssurfacetheaveragetemperatureof15℃.3.Muchoftheenergyusedtolightandheatourhomescomesfromfossilfuels.4.ThebiggestproducerofgreenhousegasesistheUnitedStatesofAmerica.5.Carbondioxidestaysintheatmosphereforcenturieswhileothergreenhousegasesstayintheatmosphereonlyforadayorless.6.Low-lyingcountriesfeeltheirveryexistenceisindangerfromrisingsealevels.7.Manyscientistsbelievethathumanactivitieshavecausedtheearth’stemperaturetorise.8.Scientistswanttofindoutaboutfutureclimatechangesandtheireffectsonourenvironment.9.Intheyearsahead,theleveloftheseacouldrisebyseveralmetersbecauseofglobalwarming.10.Inthefutureouterspacemightprovideuswithnewenergysources.Period4UsingLanguageTeachingGoals:discussandreadaboutglobalwarming.learntowriteaposter.TeachingProcedures:Step1.WarmingupTurntopage30.Listentothetapeandfollowinalowvoice.Pausewherethereaderpauses.Payattentiontothepronunciationandintonation.Step2.ReadingIndividualworkWhenyoureadthetextforthesecondtimeyouaresupposedtounderlinealltheusefulcollocations.Youhavetocopythemintoyournotebook.IhopeyoucanfullyunderstandtheimportanceofexpressionsinEnglishlearning.2.GroupworkDiscussingroupsthecollocationsfromthetext.Doaprojecton…;do…about…haveeffecton…;startwith…getsuggestions;havetopowerto;makeadifference;putupwith…comefrom…reducethecarbondioxidecontent;bestartedwith…;useenergyin…leave…on;turn…off;turnuptheheat;rideabike;make…from…;bemadefromrecycledmaterials;saveenergy;planttreesinthegarden;absorbcarbondioxidefrom…;talkwith…about…Step3.WritingYouaregoingtomakeapostertotellyourschoolmateswaystoreducetheamountofcarbondioxideinthe