2019-2020年高考英语二轮复习 阅读理解训练2

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1、2019-2020年高考英语二轮复习阅读理解训练2阅读下列四篇短文，从每小题后所给的A,B,C或D四个选项中，选出最佳选项。ArecentstudyofancientandmodernelephantshaseupwiththeunexpectedconclusionthattheAfricanelephantisdividedintotwodistinct(不同的)species.ThediscoverywasmadebyresearchersatYorkandHarvardUniversitieswhentheywereexaminingthegene

2、ticrelationshipbetweentheancientwoollymammothandmastodontomodernelephants—theAsianelephant,Africanforestelephant,andAfricansavannaelephant.OncetheyobtainedDNAsequences(序列)fromtwofossils(化石),mammothsandmastodons,theteamparedthemwithDNAfrommodernelephants.Theyfoundtotheiramazementth

3、atmodernforestandsavannaelephantsareasdistinctfromeachotherasAsianelephantsandmammoths.ThescientistsuseddetailedgeneticanalysistoprovethattheAfricansavannaelephantandtheAfricanforestelephanthavebeendistinctspeciesforseveralmillionyears.Thedivergenceofthetwospeciestookplacearoundth

4、etimeofthedivergenceofAsianelephantsandwoollymammoths.Thisresultamazedallthescientists.Therehaslongbeendebateinthescientificmunitythatthetwomightbeseparatespecies,butthisisthemostconvincingscientificevidencesofarthattheyareindeeddifferentspecies.Previously,manynaturalistsbelievedt

5、hatAfricansavannaelephantsandAfricanforestelephantsweretwopopulationsofthesamespecies,despitetheelephants’significantsizedifferences.Thesavannaelephanthasanaverageshoulderheightof3.5metreswhiletheforestelephanthasanaverageshoulderheightof2.5metres.Thesavannaelephantweighsbetweensi

6、xandseventons,roughlydoubletheweightoftheforestelephant.Butthefactthattheylooksodifferentdoesnotnecessarilymeantheyaredifferentspecies.HowevertheprooflayintheanalysisoftheDNA.AlfredRoca,assistantprofessorintheDepartmentofAnimalSciencesattheUniversityofIllinois,said,“Wenowhavetotre

7、attheforestandsavannaelephantsastwodifferentunitsforconservationpurposes.Since1950,allAfricanelephantshavebeenconservedasonespecies.Nowthatweknowtheforestandsavannaelephantsaretwoverydistinctiveanimals,theforestelephantshouldbeeabiggerpriority(优先)forconservationpurposes.”1.Oneofth

8、efossilsstudiedbytheresearchersis