第三节 概括词汇类(2017·江苏)PopulationChangeWhyistheworld’spopulationgrowing？Theanswerisnotwhatyoumightthink.Thereasonfortheexplosionisnotthatpeoplehavebeenreproducinglikerabbits，butthatpeoplehavestoppeddroppingdeadlikeflies.In1900，peoplediedattheaverageageof30.By2000theaverageagewas65.Butwhileincreasinghealthwasatypicalfeatureofthe20thcentury，decliningbirthratecouldbeadefiningoneofthe21st.Statisticsshowthattheaveragenumberofbirthsperwomanhasfallenfrom4.9intheearly1960sto2.5nowadays.Furthermore，around50%oftheworld’spopulationliveinregionswherethefigureisnowbelowthereplacementlevel (i.e.2.1birthsperwoman) andalmostalldevelopednationsareexperiencingsub-replacementbirthrate.Youmightthinkthatdevelopingnationswouldmakeuptheloss(especiallysince80%oftheworld’speoplenowliveinsuchnations)，butyou’dbewrong.Decliningbirthrateisamajorprobleminmanydevelopingregionstoo，whichmightcausecatastrophicglobalshortagesofworkforcewithinafewdecades.AgreatdeclineinyoungworkforceislikelytooccurinChina，forinstance.Whatdoesitimply？First，Chinaneedstoundergorapideconomicdevelopmentbeforeapopulationdeclinehitsthecountry.Second，ifotherfactorssuchastechnologyremainconstant，economicgrowthandmaterialexpectationswillfallwellbelowrecentstandardsandthiscouldinvitetrouble.Russiaisanothercountrywithpopulationproblemsthatcouldbreakitseconomicpromise.Since1992thenumberofpeopledyinghasbeenbiggerthanthatofthosebeingbornbyamassive50%.Indeedofficialfiguressuggestthecountryhasshrunkby5%since1993andpeopleinRussialiveashorterlifenowthanthosein1961.Whyisthisoccurring？Nobodyisquitesure，butpoordietandabovealllong-timealcoholismhavemuchtodowithit.Ifcurrenttrendsdon’tbend，Russia’spopulationwillbeaboutthesizeofYemen’sbytheyear2050.InthenorthofIndia，thepopulationisboomingduetohighbirthrates，butinthesouth，wheremosteconomicdevelopmentistakingplace，birthrateisfallingrapidly.Inafurthertwist，birthrateishighestinpoorlyeducatedruralareasandlowestinhighlyeducatedurbanareas.Intotal，25%ofIndia’sw...
