2020年英语六级仔细阅读练习题(一).docx

2020年英语六级仔细阅读练习题（1）Scatteredthroughtheseasoftheworldarebillionsoftonsofsmallplantsandanimalscalledplankton.Mostoftheseplantsandanimalsaretoosmallforthehumaneyetosee.Theydriftaboutlazilywiththecurrents,providingabasicfoodformanylargeranimals.Planktonhasbeendescribedastheequivalentofthegrassesthatgrowonthedrylandcontinents,andthecomparisonisanappropriateone.Inpotentialfoodvaluehowever,planktonfaroutweighsthatofthelandgrasses.Onescientisthasestimatedthatwhilegrassesoftheworldproduceabout49billiontonsofvaluablecarbohydrateseachyear.Thesea’splanktongeneratesmorethantwiceasmuch.Despiteitsenormousfoodpotential,littleeffortwasmadeuntilrecentlytofarmplanktonaswefarmgrassesonland.Nowmarinescientistshaveatlastbeguntostudythispossibility,especiallyasthesea’sresourcesloomevenmoreimportantasameansoffeedinganexpandingworldpopulation.Nooneyethasseriouslysuggestedthat“planktonburgersmaysoonbecomepopulararoundtheworld.Asapossiblefarmedsupplementaryfoodsource,however,planktonisgainingconsiderableinterestamongmarinescientists.Onetypeofplanktonthatseemstohavegreatharvestpossibilitiesisatinyshrimplikecreaturecalledkrill.Growingtotwoorthreeincheslong,krillprovidethemajorfoodforthegiantbluewhale,thelargestanimalevertoinhabittheEarth.Realizingthatthiswhalemaygrow100feetandweigh150tonsatmaturity,itisnotsurprisingthateachonedevoursmorethanonetonofkrilldaily.Krillswimaboutjustbelowthesurfaceinhugeschoolssometimesmileswide,mainlyinthecoldAntarctic.Becauseoftheirpinkcolor,theyoftenappearasasolidreddishmasswhenviewedfromashiporfromtheair.Krillareveryhighinfoodvalue.Apoundofthesecrustaceanscontainsabout460calories—aboutthesameasshrimporlobster,towhichtheyarerelated.Ifthekrillcanfeedsuchhugecreaturesaswhales,manyscientistsreason,theymustcertainlybecontendersasnewfoodsourceforhumans.1 .Whichofthefollowingbestportraystheorganizationofthepassage?A.Theauthorpresentstheadvantagesanddisadvantagesofplanktonasafoodsource.B.Theauthorquotespublicopiniontosupporttheargumentforfarmingplankton.C.Theauthorclassifiesthedifferentfoodsourcesaccordingtoamountofcarbohydrate.D.Theauthormakesageneralstatementaboutplanktonasafoodsourceandthenmovestoaspecificexample.2 .Accordingtothepassage,whyisplanktonregardedtobemorevaluablethanlandgrasses?A.Itiseasiertocultivate.B.Itproducesmorecarbohydrates.C.Itdoesnotrequiresoil.D.Itismorepalatable.3 .Whydoestheauthormention“planktonburgers”?A.Todescribetheappearanceofonetypeofplankton.B.Toillustratehowmuchplanktonawhaleconsumes.C.Tosuggestplanktonasapossiblefoodsources.D.Tocomparethefoodvaluesofbeefandplankton.4 .Whatismentionedasoneconspicuousfeatureofkrill?A.Theyarethesmallestmarineanimals.B.Theyarepinkincolor.C.Theyaresimilarinsizetolobsters.D.Theyhavegrasslikebodies.5 .Theauthormentionsallofthefollowingasreasonswhyplanktoncouldbeconsideredahumanfoodsourceexceptthatitis___.A.highinfoodvalue.B.inabundantsupplyintheoceans.C.anappropriatefoodforotheranimals.D.freeofchemicalsandpollutants.答案：DBCBD。