Unit4SectionB（readingplus）课件人教版八年级英语下册

Unit4TheWondersofNatureSectionB（ReadingPlus）LocatedinAfrica,theSaharaDesertspreadsacross30percentofthecontinent.Thisvastdesert,alsoknownas“thegreatdesert”inArabic,isabout9millionsquarekilometresinsize.Itisalsoatleast4.6millionyearsold.Thismeansthatitisoneoftheoldestplacesintheworld.TheSaharaDesertReadandlearn横跨；遍布大陆；陆地；洲辽阔的；巨大的阿拉伯语在尺寸上；在大小方面至少Alldesertsaredry,andtheSaharaisbothdryandhot.Itisthelargesthotdesertintheworld.Wemaythinkthatalldesertsarehot,butinfactsomedesertsareverycold!ManyscientistsbelievethatAntarctica,forexample,isatypeofcolddesert.一种MostoftheSaharaisrockyground.Buttherearealsoplaceswithgrass,lakes,mountains,andevensandseas.岩石的；多岩石的Asandseaisjustwhatitsoundslike—itlookslikeaseaofsand!Whenthewindblows,thesandlookslikewaves.LifeintheSaharaisdifficult.AbouttwomillionpeopleliveintheSahara.Theyusuallymovefromplacetoplace.ThereiswaterinafewpartsoftheSahara,andsomepeopleliveintheseplacesallyearround.what引导的表语从句，说明沙海是什么样的到处；从一个地方到另一个地方全年不定式作目的状语，说明大耳朵的作用Notmanyanimalscanliveinaplacewithsuchadryandhotclimate.Theymustadapttosurvive.Camels,forexample,goforalongtimewithoutdrinkingwater.Whentheydofindwater,theycandrinkmorethan100litresofitin13minutes!Fennecfoxesliveinthedeserttoo.Theyhavelargeearstohelptheirbodiesstaycool.适应（新情况）adaptto适应某物骆驼此处的do是强调助动词，当句中无其他助动词时，用于加强语气。升耳廓狐Today,theworld’slargesthotdesertisgettingevenbigger.Itisnowabout10percentlargerthanwhatitwasaboutacenturyago.Butwhyisitgrowing?Somescientistsbelievethatpartofthereasonisclimatechange.Astemperaturesrise,summersinAfricagrowhotterandlessrainfalls.Waterbodiesgetsmallerandthegroundgetsdrieranddrier.Ifwedonottakeeffectivemeasures,thedesertwillkeepgrowing!百年；世纪水体比较级+and+比较级越来越……采取有效的措施WhatdoyoualreadyknowabouttheSaharaDesert?DiscussWhatIalreadyKonwKWhatIWanttoKnowWWhatIHaveLearnedLKWLchartdryandhotinAfricathelargesthotdesertintheworldCamelslivethereWhatelsedoyouwanttoknowabouttheSahara?DiscussWhatIalreadyKonwKWhatIWanttoKnowWWhatIHaveLearnedLKWLchartdryandhotinAfricathelargesthotdesertintheworldCamelslivethereHowbigistheSahara?Howoldisitexactly?Whatplantsandanimalslivethere?Howdopeoplelivethere?......Nowwehavesomanyinterestingquestions!Let’sreadthetexttoseeifwecanfindtheanswers.PredictionTitlePicture+Whatcanyouseeinthepicture?Icanseeasmallfoxwithbigears.Whydoyouthinkithassuchbigears?Tohelpitstaycoolinthehotdesert!fennec/ˈfenek/foxesWhatmightthetexttalkabout?SkimmingWhattypeofwritingisthetext?A.Exposition(说明文）B.Narrative（记叙文）C.Argumentation（议论文）Howmanyparagraphsarethere?6Findthetopicsentencesofeachparagraph.Tip:Thetopicsentenceusuallyliesatthebeginningortheendofaparagraph.SkimmingHowmanypartscanwedividethetextinto?ThreWhat’sthemainideaofeachpart?BasicfactsabouttheSaharaDesert.LifeintheSahara.TheproblemtheSaharaisfacing.Careful-readingReadpara.1andcompletethetable.BasicfactsabouttheSaharaDesert.Location&SizeItisin__________.Itspreadsacross____________ofthecontinent.Itisabout___________squarekilometresinsize.Age-Itisatleast____________yearsold.Africa30percent9million4.6millionCareful-readingReadpara.2andpara.3andcompletethetable.BasicfactsabouttheSaharaDesert.ClimateItisboth__________and__________.Itis_____________________desertintheworld.LandscapeMostofitis__________ground.Italsohasgrass,lakes,mountains,and__________.dryhotthelargesthotdesertrockysandseasSaharaisahotanddryplace.Howcanpeopleandanimalssurvivethere?Howisthelifethere?CategorySpecialwaystosurvivePeopleMove____________________.Live___________allyearround.CamelsCangoforalongtime____________________.Candrink__________________ofwaterin13minuteswhentheydofindwater.FennecfoxesHavelargeearstohelptheirbodies___________.Careful-readingReadpart2(para.4andpara.5)andcompletethetable.fromplacetoplacenearwaterwithoutdrinkingwatermorethan100litresstaycoolLifeintheSaharaisdifficult,butpeopleandanimalsadapttosurvive.Butlookatthedesertitself—doesitstaythesameallthetime?Careful-readingReadpart3(para.6)andanswerthequestions.1.

HowmuchlargeristheSaharathanaboutacenturyago?Itisnowabout10percentlargerthanitwasaboutacenturyago.2.

Whyisitgrowing?Somescientistsbelievethatpartofthereasonisclimatechange.Astemperaturesrise,summersinAfricagrowhotterandlessrainfalls.Waterbodiesgetsmallerandthegroundgetsdrieranddrier.3.

Whatwillhappenifwedon’ttakeaction?Thedesertwillkeepgrowing.Discuss1.

砍伐树木(Deforestation)-Peoplecutdowntoomanytreesforfirewoodorfarming.-Treeshelpkeepthesoilandwater.Withouttrees,thelandbecomesdryandturnsintodesert.2.

过度放牧(Overgrazing)-Toomanysheepandgoatseatupallthegrass.-Thesoilisleftbare.Windcaneasilyblowitaway,andthelandbecomesdesert.3.

过度开垦(Over-cultivation)-Farmersplantcropsondrylandtoooften,withoutlettingthesoilrest.-Thesoillosesitsnutrientsandcan’tgrowplantsanymore.4.

水资源过度开发(Overuseofwaterresources)-Peopleusetoomuchgroundwaterforfarminganddailylife.-Riversandlakesdryup,andthelandaroundthembecomesdesert.5.

土壤侵蚀(Soilerosion)-Withoutplantstoprotectthesoil,windandrainwashthegoodsoilaway.-Thelandbecomestoopoortogrowanything,soitturnsintosand.WhatotherreasonsmightcausetheSaharatogrow?1.

Plantmoretrees(植树造林)-Wecanplantmoretreesandgrass.-Theycanholdthesoilandkeepwaterintheground.2.

Usewaterwisely(合理用水)-Weshouldsavewaterindailylife(e.g.,turnofftapswhennotusingthem).-Farmerscanuselesswaterforgrowingcrops.3.

Controlgrazing(控制放牧)-Farmersshouldnotkeeptoomanysheeporgoatsinoneplace.-Thisway,thegrasscangrowback.4.

Protectthesoil(保护土壤)-Weshouldletdrylandrestsometimes,notplantcropsallthetime.-Thishelpsthesoilgetbackitsnutrients.5.

Learnandtellothers(宣传环保)-Wecanlearnmoreaboutdesertification.-Wecantellourfamilyandfriendstoprotecttheenvironmenttoo.Whatcanwedotohelpstopthedesertfromgrowing?DiscussWhathaveyoulearnedabouttheSahara?SummaryWhatIalreadyKonwKWhatIWanttoKnowWWhatIHaveLearnedLKWLchartdryandhotinAfricathelargesthotdesertintheworldCamelslivethereHowbigistheSahara?Howoldisitexactly?Whatplantsandanimalslivethere?Howdopeoplelivethere?......LocationSize&AgeGeographyLifeGrowthProtection...1Readthetextandcompletethemindmap.inAfricaabout9millionsquarekilometresatleast4.6millionyearsoldmostlyrockyground,withgrass,lakes,mountains,andsandseasabouttwomillionpeople,camels,andfennecfoxesabout10%inlast100years2Discussthequestions.1.

Howislifeinthedesertdifferentfromotherplaces?Lifeinthedesertisverydifferentfromotherplacesbecausethereisnotmuchwater,anditisveryhot.2.

Wouldyouliketovisit/liveintheSahara?Why?IwouldliketovisittheSaharaDesert,butnottolivethere.Iwouldliketoseethesandseasa