人教八下英语Reading Plus《Unit 4》课件

Unit4ReadingPlusTheSaharaDesertLocatedinAfrica,theSaharaDesertspreadsacross30percentofthecontinent.Thisvastdesert,alsoknownas“thegreatdesert”inArabic,isabout9millionsquarekilometresinsize.Itisalsoatleast4.6millionyearsold.Thismeansthatitisoneoftheoldestplacesintheworld.作定语大约that引导宾语从句Alldesertsaredry,andtheSaharaisbothdryandhot.Itisthelargesthotdesertintheworld.Wemaythinkthatalldesertsarehot,butinfactsomedesertsareverycold!ManyscientistsbelievethatAntarctica,forexample,isatypeofcolddesert.事实上作插入语MostoftheSaharaisrockyground.Buttherearealsoplaceswithgrass,lakes,mountains,andevensandseas.Asandseaisjustwhatitsoundslike—itlookslikeaseaofsand!Whenthewindblows,thesandlookslikewaves.表语从句LifeintheSaharaisdifficult.AbouttwomillionpeopleliveintheSahara.Theyusuallymovefromplacetoplace.ThereiswaterinafewpartsoftheSahara,andsomepeopleliveintheseplacesallyearround.与具体数字连用时，million用单数形式Notmanyanimalscanliveinaplacewithsuchadryandhotclimate.Theymustadapttosurvive.Camels,forexample,goforalongtimewithoutdrinkingwater.Whentheydofindwater,theycandrinkmorethan100litresofitin13minutes!Fennecfoxesliveinthedeserttoo.Theyhavelargeearstohelptheirbodiesstaycool.适应Today,theworld’slargesthotdesertisgettingevenbigger.Itisnowabout10percentlargerthanwhatitwasaboutacenturyago.长难句分析：主句是Itisnowabouttenpercentlarger，abouttenpercentlarger是形容词比较级短语作表语；从句thanwhatitwasaboutacenturyago是由比较连词than引导的比较状语从句。Butwhyisitgrowing?Somescientistsbelievethatpartofthereasonisclimatechange.Astemperaturesrise,summersinAfricagrowhotterandlessrainfalls.Waterbodiesgetsmallerandthegroundgetsdrieranddrier.Ifwedonottakeeffectivemeasurestostopclimatechange,thedesertwillkeepgrowing!引导时间状语从句1Readthetextandcompletethemindmap.Africa“thegreatdesert”inArabicabout9millionsquarekilometresItisnowabout10percentlargerthanwhatitwasaboutacenturyago.atleast4.6millionyearsoldpeople,camels,andfennecfoxesMostoftheSaharaisrockyground.Therearealsoplaceswithgrass,lakes,mountains,andevensandseas.2Discussthequestions.1.Howislifeinthedesertdifferentfromotherplaceswherepeoplelive?Peoplewholiveinthedesertusuallymovefromplacetoplace.2.WouldyouliketovisittheSaharaDesertorevenlivethereforawhile?Iwouldliketovisititandseethesandseasandmountains,butIdonotwanttolivetherebecauseitistoohotanddry.3.WhatdoyouthinkwillhappeniftheSaharakeepsgettingbigger?Whatshouldwedoaboutit?IftheSaharakeepsgrowing,morelandwillturnintodesert,causinglessrainandsmallerlakes.Thiswillmakeitharderforpeopletogrowfoodorfindwater.Tostopthisexpansion,wemustcombatcl