Unit4GlobalWarming教學(xué)設(shè)計教學(xué)目標Ⅰ.教學(xué)內(nèi)容分析本單元的中心話題是人類當今面對的環(huán)境問題，主要探討了“全球變暖”和“節(jié)約能源”等方面的問題。由于人類過多使用不可再生能源，大氣中二氧化碳的含量逐年增加，導(dǎo)致全球氣溫上升。通過學(xué)習本單元，讓學(xué)生了解能源分為“不可再生能源”和“可再生能源”，幫助學(xué)生樹立“節(jié)約能源、保護環(huán)境”的主人翁意識。語言知識和語言技能主要圍繞“全球變暖”和“節(jié)約能源”這一主題設(shè)計的。“熱身”(Warmingup)部分要求學(xué)生列舉家中、學(xué)?；蚱渌胤绞褂媚茉吹奈矬w，指出這些能源的來源，并盡可能多地列舉不同的能源。能源可分為兩類：一類是可再利用能源；另一類是一次性能源。把前面列舉的能源按能否再利用這一標準進行分類。本部分提供了六幅圖片，教師可以從識圖開始組織教學(xué)。還可以讓學(xué)生搜集一些其他相關(guān)圖片。這六幅圖分別為：風力（windpower）、燃煤發(fā)電站（acoalpowerstation）、煉油廠（anoilrefinery）、原子能發(fā)電站（anuclearpowerplant）、太陽能接受器（solarpanels）、水壩（ahydrodam）?！白x前”(Pre-reading)部分首先介紹什么是溫室、它有什么作用，然后要求學(xué)生討論大氣中溫室氣體的作用。溫室是由玻璃構(gòu)成的建筑，主要用于花果蔬菜的培植。溫室是由玻璃構(gòu)成的建筑，主要用于花果蔬菜的培植。溫室能阻止熱量散發(fā)，因而能幫助植物度過寒冷的時期。該部分的討論有利于學(xué)生預(yù)測課文內(nèi)容和理解閱讀課文中的溫室氣體效應(yīng)?！伴喿x”(Reading)部分是一篇雜志文章，主要講述了地球溫度上升的現(xiàn)象和原因。20世紀中，地球的溫度上升了華氏1度。這看上去是一個很小的數(shù)字，但相對于自然界的其他現(xiàn)象來說，這個增長速度是迅猛的。這種現(xiàn)象是自然發(fā)生的還是人為的？這個問題引起激烈的爭論。許多科學(xué)家認為，這種變化是人類燃燒礦物燃料所致。這些物質(zhì)的燃燒產(chǎn)生以二氧化碳為主的溫室氣體。正因為自然界有溫室氣體的存在，地球才不至于很冷。但大量排放二氧化碳會使地球普遍升溫。對于地球升溫，科學(xué)家有不同的看法。有些科學(xué)家認為，這個問題很嚴重。地球升溫會導(dǎo)致海水上漲、風暴、干旱、饑荒、物種毀滅和疫病等。也有科學(xué)家認為，地球升溫有利于改善人類生活，比如，莊稼長得更快、產(chǎn)量更高等。文章最后以開放性的問題結(jié)尾要求讀者思考：對于全球變暖，人類要不要采取措施？“理解”(Comprehending)部分設(shè)置了三個活動。閱讀課文中的雜志文章，練習1首先就作者、雜志名稱、文中提到的科學(xué)家、文中出現(xiàn)的曲線圖等內(nèi)容提問，并要求學(xué)生概括文章的主題。然后，練習2要求學(xué)生細讀課文，并判斷所給六個句子是否符合課文內(nèi)容。最后練習3要求學(xué)生小組討論：Weshoulddonothingaboutglobalwarming.在小組討論的基礎(chǔ)上，把全班分成正方和反方，舉行一個辯論會?！罢Z言學(xué)習”(Learningaboutlanguage)的詞匯學(xué)習部分共兩個練習。練習1讓學(xué)生重新閱讀課文并找出文中一些具有不同詞性或不同含義的生詞，分辨它們在文中的含義。練習2則要求學(xué)生使用前幾個部分所學(xué)的生詞來完成與“全球變暖”話題相關(guān)的一些句子。語法學(xué)習部分中練習1讓學(xué)生通過對比課文中it作強調(diào)作用的句子與其他句子的區(qū)別，發(fā)現(xiàn)并熟悉強調(diào)句型及其規(guī)律。練習2則要求學(xué)生針對所給句子的劃線部分轉(zhuǎn)換句型，練習使用it的強調(diào)句型。練習3則給予學(xué)生更廣闊的思維空間，讓學(xué)生根據(jù)自己對“全球變暖”話題的認識運用強調(diào)句型進行復(fù)述或表達自己的觀點?！罢Z言運用”(Usinglanguage)部分的“讀和寫”(Readingandwriting)讓學(xué)生就WHATCANWEDOABOUTGLOBALWARMING?進行討論。歐陽光給關(guān)愛地球組織雜志寫電子郵件，請求幫助。雜志回信指出，群策群力，問題可解。他們提出了幾個具體措施：1、減少電器的使用；2、盡量步行或騎自行車；3、回收玻璃、塑料、報紙等物品；4、勸父母購買節(jié)能產(chǎn)品；5、植樹；6、宣傳有關(guān)知識。閱讀之后，教師可以讓學(xué)生就文中提出的建議進行討論，并可以讓學(xué)生提出更多的建議。這樣，學(xué)生就有了充分的材料去完成寫的任務(wù)：設(shè)計一個海報，介紹減少空氣中二氧化碳含量的方法。聽力部分是大學(xué)生李斌與陳教授的一段對話，討論能源的使用問題，并學(xué)習表達“贊成”或“不贊成”的交際用語?！靶〗Y(jié)”(Summingup)部分要求學(xué)生就全球變暖、如何減少二氧化碳、強調(diào)句、相關(guān)詞語等方面進行自我評價，判定學(xué)習情況：了解還要進一步改進的地方?！皩W(xué)習建議”(Learningtip)部分介紹首字母大寫的規(guī)則，要求學(xué)生在閱讀中學(xué)會辨別人名、地名、書名、題目等。Ⅱ.教學(xué)重點和難點1.教學(xué)重點：(1)本單元的生詞和短語。(2)it的用法。(3)了解“全球變暖”、“能源的種類”和“節(jié)約能源”等方面的知識。幫助學(xué)生樹立“節(jié)約能源、保護環(huán)境”的主人翁意識。2.教學(xué)難點(1)學(xué)會表達同意和不同意、責備和抱怨等日常交際用語。(2)學(xué)習it在強調(diào)句中的用法。(3)學(xué)習如何寫一幅表達自己觀點、勸說他人節(jié)約能源、保護環(huán)境的海報。(4)學(xué)習有關(guān)氣候、能源、環(huán)保的詞匯。Ⅲ、教學(xué)課時計劃本單元用五課時：第一課時：WarmingUp第二課時：Pre-reading,Reading,Comprehending第三課時：LearningaboutLanguage第四課時：UsingLanguage第五課時：Summingup-Learning-TipⅣ、教學(xué)步驟：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 熱能Soundenergy 聲能 Chemicalenergysource 化學(xué)能源Nuclearenergy 核能 Internalenergy 內(nèi)能Kineticenergy 動能 Potentialenergy 勢能能源類型定義實例一次能源直接來自自然界而未經(jīng)加工轉(zhuǎn)換的能源化石燃料、太陽能、核能、生物燃料、水能等二次能源由一次能源直接或間接轉(zhuǎn)化而來的能源電能、煤氣、汽油、沼氣、氫能等可再生能源不隨其本身的轉(zhuǎn)化或被人類利用而減少的能源太陽能、生物能、水能、風能、地熱能等非再生能源隨其本身的轉(zhuǎn)化或被人類利用而減少的能源化石燃料、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比較●常見用法：①compare…with…把…和…比較Comparedwithhim,Iamfast.②compare…to…把…比作…Lifeisoftencomparedtovoyage.(2)comeabout發(fā)生Howdiditcomeabout?那事是怎么發(fā)生的?●常見詞組：comeacross 偶遇；碰到 comeround 恢復(fù)知覺，comealong 進展；進行 cometo 涉及；到達；共計comeout 公開；問世；出版 cometooneself 恢復(fù)知覺comeupwith 想出(4)phenomenonn現(xiàn)象Itisonlyasocialphenomenon,butnotaphenomenonofnature.Part2(Paragraph2,3,4)fueln燃料Don’tleavetheengineswitchedon.Itwastesfuel.●拓展：fuelv加油；補給燃料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資料;數(shù)據(jù)Wehaven’tgotenoughdata..(2)resultin導(dǎo)致Theaccidentresultedinthedeathoftwopassengers.Itresultedinsuccess.●拓展：resultfrom由于Hisillnessresultedfromeatingbadfood.(3)catastrophen突如其來的大災(zāi)難；大災(zāi)禍Thewarwasaterriblecatastropheinwhichmanypeopledied.(4)climaten氣候Wehaveamildclimatehere.(5)consequencen結(jié)果；后果；影響Asaconsequenceofbeinginhospital,Shellydecidedthatshewantedtobecomeanurse.●常見詞組：inconsequence因此，由此inconsequenceof…由于…的緣故(6)statevt陳述；說明Thebusmenhavestatedthatthestrikewillcontinueuntilgeneralagreementisreachedaboutpayandworkingconditions.(7)range n&v①種類；范圍；幅度Thereisawiderangeoftemperature.氣溫變化很大。②vi(在一定范圍內(nèi))變化Thenumberrangesbetween5and15.③vt排列，整理Pleaserangethegoodsneatlyintheshopwindow.Part4(Paragraph10)(1)buildup逐步建立；增加；增進Weneedtobuildupourreputation.Trafficisbuildinguponroadsintothecity.(2)Keepon繼續(xù)Pricekeptonincreasing.Hedidn’tstoprunning;hejustkepton.●拓展：keepondoing與keepdoing的區(qū)別：keepondoing表示動作反復(fù)發(fā)生；keepdoing表示狀態(tài)或動作的持續(xù)。Hekeptonstandingupinclass.他在課堂上一再地站起來。Hekeptstandingthereforhalfanhourwithoutmoving.他一動不動地在那里站了半個小時。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構(gòu)成的英語強調(diào)結(jié)構(gòu)①強調(diào)句型的基本結(jié)構(gòu)形式為：“Itis/was+被強調(diào)部分+that+句子的其余部分”當被強調(diào)部分是人時that也可以換成who。如：ProfessorLiuteachesusEnglishthisyear.今年劉教授教我們英語。ItisprofessorLiuwho/thatteachesusEnglishthisyear.(強調(diào)主語)ItisEnglishthatProfessorLiuteachesusthisyear.(強調(diào)賓語)ItwasthisyearthatProfessorLiuteachesusEnglish.（強調(diào)狀語）②強調(diào)句型的一般疑問句式：Is/Wasit+被強調(diào)部分+that+句子的其余部分？IsitProfessorLiuwho/thatteachesusEnglishthisyear?③強調(diào)句型的特殊疑問句式：特殊疑問句+is/wasit+被強調(diào)部分+that+句子的其余部分？WhoisitthatteachesusEnglishthisyear?WhatsitthatProfessorLiuteachesusthisyear?2.強調(diào)句型的特點去掉Itis(was)及that(who)后，在不添詞、不減詞的前提下能重新構(gòu)成一個意義完整的句子。這也是判斷一個句子是否是強調(diào)句型的依據(jù)。3.強調(diào)句型的時態(tài)如果原句中謂語動詞使用的是現(xiàn)在或?qū)頃r間范疇的時態(tài)（一般現(xiàn)在時、現(xiàn)在進行時、現(xiàn)在完成/現(xiàn)在完成進行時、一般將來時、將來進行時、將來完成時等），用Itis…that…。如果原句中謂語動詞為過去時間范疇的時態(tài)（一般過去時、過去進行時、過去完成時、過去將來時等），則用Itwas…that…。4.not…until句型的強調(diào)句型當被強調(diào)的是not…until句型時，應(yīng)將not置于until之前，主句由否定句改為肯定句。如：Hedidn’tleaveuntil11o’clock.他直到11點才離開。Itwasnotuntil11o’clockthatheleft.（強調(diào)notuntil時間狀語）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(癥狀)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…h(huán)aveeffecton…;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