一、阅读理解单项选择题Waterproblemsinthefuturewillbecomemoreintenseandmorecomplex.Ourincreasingpopulationwilltremendouslyincreaseurbanwastes,primarilysewage.Ontheotherhand,increasingdemandsforwaterwilldecreasesubstantiallytheamountofwateravailablefordilutingwastes.Rapidlyexpandingindustrieswhichinvolvemoreandmorecomplexchemicalprocesseswillproducelargevolumesofliquidwastes,andmanyofthesewillcontainchemicalswhicharepoisonous.Tofeedourrapidlyexpandingpopulation,agriculturewillhavetobeintensified.Thiswillinvolveever-increasingquantitiesofagriculturechemicals.Fromthis,itisapparentthatdrasticstepsmustbetakenimmediatelytodevelopcorrectivemeasuresforthepollutionproblem.Therearetwowaysbywhichthispollutionproblemcanbelessened.Thefirstrelatestothetreatmentofwastestodecreasetheirpollutionhazard.Thisinvolvestheprocessingofsolidwastes"priorto"disposalandthetreatmentofliquidwastes,oreffluents(废料),topermitthereuseofthewaterorbestreducepollutionuponfinaldisposal. Asecondapproachistodevelopaneconomicuseforallorapartofthewastes.Farmmanureisspreadinfieldsasanutrient(养料)ororganicsupplement.Effluentsfromsewagedisposalplantsareusedinsomeareasbothforirrigationandforthenutrientscontained.Effluentsfromotherprocessingplantsmayalsobeusedasasupplementalsourceofwater.Manyindustries,suchasmeatandpoultryprocessingplants,arecurrentlyconvertingformerwasteproductionintomarketablebyproducts.Otherindustrieshavepotentialeconomicusesfortheirwasteproducts.1.Thepurposeofthispassageis_______.
A
to warn the reader of the dwindling water supply
B
to explain industrial uses of water
C
to acquaint the reader with water pollution problems
D
to demonstrate various measures to solve the pollution problem Which of the following
