浙江省杭州市2019年中考英语一轮复习课时训练03Units1_4七下课件.docx

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1、课时训练(三)　Units1-4(七下)(限时:30分钟)Ⅰ.[2018·连云港]阅读理解　　Batsaretheonlymammalsthatcanflyagreatdistance,buttheyhaveanotherability.Manybatsliveaverylongtimeforananimaltheirsize.　　Europeanresearchersarestudyingbatstounderstandwhytheylivesolong.Theyhopetomakediscoveriestofighttheagingprocess(过程)inhumanb

2、eings.　　Lastweek,thegroupofscientistssaidtheyhadfoundimportantbiologicalqualitiesinsomebatspecies.Thegroupstudiedbatchromosomes(染色体),alineofgenesfoundinthenucleus(核)ofcells.Thescientistsweremostinterestedinpartsconnectedtotheendsofthechromosomes.Theyarecalledtelomeres(端粒).Telomeresprotectt

3、heendsofchromosomes,whichshorteneachtimeacelldivides.Scientistsbelievethisshorteningprocesscausescellstobreakdown.　　　　. 　　AreportonbatswaspublishedthismonthinthejournalScienceAdvances.　　AmongtheleadersofthestudywasEmmaTeeling,abiologistwithUniversityCollegeDublininIreland.Teelingsaidstudyi

4、nglong-livingmammalsthathavedevelopedwaystofightaging“isanotherwaytoprovethemolecular(分子)basisofextended‘healthlength.’”Sheaddedthatstudyingbatsmadescientistsabletolearnmoreabouttheprocesses“thatdrivehealthyaging.”　　TheEuropeanresearchersstudied493batsfromfourbatspecies.Thegroupusedinforma

5、tionthathadbeengatheredovermorethan60years.Oftheseanimals,thegreatermouse-earedbatgenerallylivedthelongest,anaverageof37years.　　Thescientistssaidthisandarelatedspecies,whicharegroupedtogetherunderthenameMyotis,hadtelomeresthatdidnotshortenwithage.AnotherMyotisbatholdstherecordforoldestage,

6、reaching41years.　　Thescientists’findingssuggestthatthesebats’cellshavetheabilitytokeepandrepairtheirtelomeres.This,theysaid,helpsguardagainsttheagingprocess.Basedonitsbodysize,abatlikethegreatermouse-earedbatwouldbeexpectedtolivefouryears.But,thesemammalshavebeenfoundtolivenearly10timeslon

7、gerthanthat.　　ThescientistsfoundthatEighteenofthesearebats.TheonlyexceptionisanunusualAfricanrodent,thenakedmolerat.1.WhichsentencecanbeputattheendofParagraph3?A.Thismakesscientistsabletostudybats.B.That’swhybatscanflyagreatdistance.C.Theysaythisiswhatcausesag