考研英语备考阅读理解练习题.docx

考研英语备考阅读理解练习题

阅读理解是考研英语必出的题型，下面小编为大家带来了考研英语备考阅读理解练习题，欢迎大家阅读，希望对大家有所帮助。IFYOU'RECONFUSEDBYALLthenewsaboutthehealtheffectsofeatingfish，you'renotalone.Ononehand，theomega-3fattyacidsinfishareknowntoreducetheriskofheartdisease，astheAmericanHeartAssociationremindedustwoweeksagowhenitrestateditsrecommendationthateverybodyeatatleasttwofishservingsaweek.Ontheotherhand，fishthatfeedincontaminatedwaterwayscontainhighlevelsofmercury，whichcanleadtocognitiveproblemsindevelopingbrains.That'swhypregnantwomenandnursingmothersareadvisedtolimittheirconsumption.Asifthatweren'tconfusingenough，twonewstudiespublishedlastweekintheNewEnglandJournalofMedicineinvestigatedthepossibleeffectsofmercuryontheheart，andtheyseemtohavereachedcontradictoryconclusions.Onefoundnoclearlinkbetweenmercurylevelsandheartdisease;theotherfoundthatmenwithhighlevelsofmercuryintheirtoenailsweremorelikelytosufferaheartattackthanthosewithlowlevels.Whatarewetomakeofthis?Thefirstthingtorememberisthatthisishowscienceproceeds，byfitsandstartsandseeminglycontradictoryresultsthatgetresolvedonlybyfurtherstudy.Thesecondisthatnotallfisharecreatedequal.Comparedwithalltheotherthingsyoumighteat，fishareanexcellentsourceofprotein.Theytendtoeatalgaeaspartoftheirnaturallifecycle，convertingitintoomega-3fattyacidsthatcanimproveyourcholesterolprofile.Butit'salsotruethatourwaterwayshavebecomeincreasinglycontaminatedwithallsortsofpollutants，includingmercury，andthatthesepollutantstendtoaccumulateatdifferentlevelsindifferentspecies.Thefishmostatriskarepredatorshighinthepelagicfoodchain，suchasswordfishandsharks(seechart)。Itwastotesttheeffectsofmercuryontheheartthatthetwonewstudiescomparedthemercurylevelsinclippingsfromtoenails，whereheavymetalstendtobedeposited.Inonestudy，researchersledbyDr.EliseoGuallaratJohnsHopkinsfoundthatEuropeanandIsraelimenwiththehighestmercurylevelswerenearly2.2timesaslikelytohaveaheartattackasthosewiththelowestlevels.Theotherstudy，ledbyDr.WalterWillettattheHarvardSchoolofPublicHealth，lookedataselectionofAmericanmenand