E
Theneedtofeedagrowingpopulationisputtingmuchpressureontheworld’ssupplyofwater.With97%oftheworld’swatertoosaltytobedrunkorusedinagriculture,theworldwidesupplyofwaterneedscarefulmanagement,especiallyinagriculture.Althoughtheideaofawatershortage(短缺)seemsstr angetosomeonefortunateenoughtoliveinahighrainfullcountr y,manyoftheworld’sagriculturalindustr iesexperienceconstantwatershortages.
Althoughdamscanbebuilttostorewaterforagriculturaluseindryareasanddryseaons,thecostsofwaterredistr ibution(重新分配)areveryhigh.Notonlyistherethecostoftheengineeringitself,butthereisalsoanenvironmentalcosttobeconsidered.Wherevalleys(山谷)arefloodedtocreatedams,housesarelostandwildlifehomesdestr oyed.Besides,watermanyfloweasilythroughpipestofields,butitcannotbetr ansportedfromonesideoftheworldtotheother.Eachcountr ymustthereforerelyonthemanagementofitsownwatertosupplyitsfarmingrequirements.
Thisisparticularlytr oublingrocountr ieswithagriculturalindustr iesinareasdependentonirrigation(灌溉).InTexas,farmers’overuseofirrigationwaterberesultedina25%redcutionofthewaterstores.IntheCentr alValleyareaofsoutheasternUSA,ahugewaterengineeringprojectprovidedwaterforfarmingindryvallege,butmuchofthewaterusehasbeenpoorlymanaged.
SaudiArabia’sattemptstogrowwheatindesertareashavebeenthepumpingofhugequantitiesofirrigationwaterfromundergroundreserves.Becausethereisnorainfallintheseareas,suchreservescanonlydecrease,anditisbelievedthatfiftyyearsofpumpingwillseethemrundry.
72.Fromthefirsttwoparagraphswelearntthat_______.
A.muchoftheworld’swaterisavailableforuse
B.peopleinhighrainfllcountr iesfeellucky
C.thecostsofwaterredistr ibutionshouldbeconsidered
D.watercanbeeasilycarriedthroughpipesacrosstheworld
正确答案:C


