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1、Anarticlepublishedrecentlyinthescientificjournal阅读理解答案 AnarticlepublishedrecentlyinthescientificjournalNatureissheddingnewlightonanimportant,butsofarlittlehasbeenappreciated,aspectofhumanevolution.Inthisarticle,ProfessorsDennisBramble,andDanielLiebermansu
2、ggestthattheabilitytorunwasadecisivefactorinthedevelopmentofourspecies.Accordingtothetwoscientists,humanspossessanumberofanatomical（人体结构的）featuresthatmakethemsurprisinglygoodrunners.“Weareveryconfidentthatstrongselectionforrunning，whichcameattheexpenseofth
3、ehistoricalabilitytoliveintrees-washelpfulintheoriginofthemodernhumanbodyform,”saysBramble,abiologyprofessorattheUniversityofUtah. Traditionalthinkinguptonowhasbeenthattheuprightbodyformofmodernhumanshascomeaboutasaresultoftheabilitytowalk,andthatrunningi
4、ssimplyaby-productofwalking.Furthermore,humanshaveusuallybeenregardedaspoorrunnerscomparedtosuchanimalsasdogs,horsesorantelopes.However,thisisonlytrueifweconsiderfastrunningovershortdistances.EvenOlympicathletecanhardlyrunasfastasahorsecangallop,andcanonly
5、keepupatopspeedforfifteensecondsorso.Horsesandantelopes,ontheotherhand,canrunattopspeedforseveralminutes,clearlyoutperformingusinthisrespect.Butwhenitcomestolong-distancerunning,humansdoastonishinglywell.Theycanmaintainasteadypaceformiles,andtheiroverallsp
6、eedcomparesfavorablywiththatofhorsesordogs. BrambleandLiebermanexaminedtwenty-sixanatomicalfeaturesfoundinhumans.Oneofthemostinterestingoftheseisthenuchalligament（颈背的韧带）.Whenwerun,itisthisligamentthatpreventsourheadfrompitchingbackandforthorfromsidetoside
7、.Therefore,weareabletorunwithsteadyheadsheldhigh.Thenuchalligamentisnotfoundinanyothersurvivingprimates（灵长类动物）,althoughthefossil（化石）recordshowsthatHomoerectus,anearlyhumanspeciesthatwalkedupright,muchaswedo,alsohadone.ThenthereareourAchillestendons（跟腱）atth
8、ebacksofourlegs,whichhavenothingtodowithwalking.Whenwerun,thesetendonsbehavelikesprings,helpingtopushusforward.Furthermore,wehavelow,wideshoulders,virtuallydisconnectedfromourskulls(thebonypartofthehead),anot
