英美文化背景与国家概况之美国地理课件

WhiteHouse

2011生物技术王传鑫2114122259

contents(156-162)1、LandResource2、RiversandLakes3、ForestsandMineralResources4、NewProblemsUncleSam

SatellitemapofAmerica卫星地图中的美国TopographicmapoftheUnitedStatesofAmerica美国地形图LandResource

About47%ofAmerica’slandareacanbeusedforagriculturalpurposes，including400millionacresofarable（适于耕种的）croplandand900millionacresofpermanentpastureland（牧场）。

ThemainriversandmountainsofAmericaRiversandlakesMississippiRiver,itflowsabout6400kilometersfromitsnorthwesternsourceintheRockiestotheGulfofMexico,ItstributariesincludenearlyalltheriverswestoftheAppalachianmountains(阿帕拉契山脉)andtheeastoftheRockies.

BigsteamshiponMississippi

Mississippi

BigdamonMississippi

Rockies

Potomacriver(波托马克河),itisfamousnotonlybecauseWashingtonD.C,itisregardedasthetraditionaldividinglinebetweentheSouthandtheNorth.ThesceneryofPotomacriverThesceneryofPotomacriverGrandCanyon(科罗拉多大峡谷)Greatlakes,ofthesefivelakesonlyone,LakeMichigan,belongstoAmericacompletelywhiletheotherfouraresharedwithCanada.Thesefivelakes,withanareaofabout240000squarekilometers,constitutethelargestlakegroupintheworld.

Greatlakes五大湖

Greatlakes五大湖

Lakesuperior

LakeMichigan

LakeHuronLakeErie

LakeOntarioNiagaraFalls

Thefivelakesslopedownwardtowardstheeast.LakeErieisover100metershigherthanLakeOntarioandtheriverthatconnectsthemiscalledNiagara（尼亚加拉）River.ThesteepdropinelevationgivesbirthtotheNiagaraFalls,itattractslargenumbersofvisitorsfromaroundtheworld.NiagaraFallsNiagaraFallsThebiggestfallsintheworld

NiagaraFalls

NiagaraFallsAmericahasbeenknownforitsrichforestresources.WhenthefirstEuropeancolonistsarrived,Americawasstillcoveredwithdenseforests,stretchingabout1600kilometersinland(国内的)fromtheAtlanticCoastline.

Todayaboutone-thirdoftheUnitedStatesisstillcoveredwithforests

Thedistributionoftheforests

ForestsandMineralResources

ThebiggesttreeintheworldSequoia(红杉)

3000yearsoldDiameter：6metersTowers：100metersTheUnitedStatesisrichinmineralresources.Itranksamongthecountrieswiththegreatestreserves(储藏量)ofcoal,ironore,andoil.Italsoabounds(富于)inlead（铅）,copper（铜）,zinc（锌）,gold,aluminum（铝）,phosphate（磷酸）rock,andsilver.NewProblemsofmodernAmerica

Afterthesecondworldwar,Americachangedfromanationthatexportedrawmaterialsintoonethatimportedthesecommodities(商品).Excessiveexplorationsandlargeconsumptionhaveexhaustedmanyresourcesthatarenotrenewable.Alaskaisrichinoil,butintermsofagriculture,itisstillan“icebox”Nowabout90%mineralsmostnecessarytothecountryarepartiallyimportedfromabroad.Largeimportationofrawmaterials，especiallyoil，isthemajorcauseofAmerica’sgrowingdeficit（赤字）inforeigntrade.Dependenceonimpor