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lesson38TheWorldisaBigPlace行星Earthisaplanet.AsiaAfricaEuropeAustraliaNorthAmericaSouthAmericaAntarcticaplanetbilliontotalincreasesurfaceIndianAtlanticArctic行星十亿，千兆总计，总数;总的增加增大表面表层印度的，印度人大西洋的北极的Theseplacesaredry.Thedryplacesarecalleddeserts.被动态be+v.过去分词干燥的地方被称为沙漠•Theworld'spopulationwasover7billionintotal.总计，合计Itisincreasingquickly.分数的表达•三分之一onethird•四分之一onefourth/aquarter•五分之二twofifths•六分之一•八分之三分子+分母基数词+序数词（分子大于一时，分母加S）onesixththreeeighths•Onethirdoftheapplesarered.•FourninthsoftheseaisinChina.后面的谓语动词单复数取决于主语的单复数•1.in2010•by2025•by2050•2.Canpeopleliveeverywhereonearth?•Whatplacesarecalleddeserts?•3.Howmanycontinentsarethere?•4.Howmanyoceansarethere？•5.Whatweshoulddo?•1.Intheyear2010,theworld'spopulationwasover7billionintotal.•2.Itisincreasingveryquickly.•3.Andby2050,theworld'spopulationmayreach9billion.•4.Wecan'tliveinwater,andonlyaboutonethirdofourplanetisland.•5.Thesedryplacesarecalleddesert.•6.Antarcticiscoveredwithsnowandiceallyearround.