【Ifyouthinkthatrunningmarathonswillhelpyoulivealongandhealthylife，newresearchmaycomeasashock．Accordingtoarecentscientificstudy，peoplewhodoaverystrenuousworkoutareaslikelytodieaspeoplewhodonoexerciseata】

　　Ifyouthinkthatrunningmarathonswillhelpyoulivealongandhealthylife，newresearchmaycomeasashock．Accordingtoarecentscientificstudy，peoplewhodoaverystrenuousworkoutareaslikelytodieaspeoplewhodonoexerciseatall．

　　ScientistsinDenmarkhavebeenstudyingover1，000joggersandnon-joggersfor12years．Thedeathratesfromthesamplegroupindicatethatpeoplewhojogatamoderatepacetwoorthreetimesaweekforlessthantwoandahalfhoursintotalareleastlikelytodie．Thebestspeedtojogatwasfoundtobeabout5milesperhour．Theresearchsuggeststhatpeoplewhojogmorethanthreetimesaweekorathigherspeedsofover7mphdieatthesamerateasnon-joggers．Thescientiststhinkthatthisisbecausestrenuousexercisecausesstructuralchangestotheheartandarteries（动脉）．Overtime，thiscancauseseriousinjuries．

　　PeterSchnohr，aresearcherinCopenhagen，said，"Ifyourgoalistodecreaseriskofdeathandimprovelifeexpectancy，joggingafewtimesaweekatamoderatepaceisagoodstrategy．Anythingmoreisnotjustunnecessary，anditmaybeharmful．"

　　Theimplicationsofthisarethatmoderateformsofexercisesuchast'aichi，yogaandbriskwalkingmaybebetterforusthan"ironman"events，triathlonsandlong-distancerunningandcycling．AccordingtoJacobLouisMarott，anotherresearcherinvolvedinthestudy，"Youdon'tactuallyhavetodothatmuchtohaveagoodimpactonyourhealth．Andperhapsyoushouldn'tactuallydotoomuch．"

　　29．Theunderlinedword"strenuous"inParagraph1isclosestinmeaningto"___"．

　　A．hard B．regular C．practical D．flexible

　　30．TheauthorpresentssomefiguresinParagraph2to___．

　　A．suggestgivingupjogging B．showrisksofdoingsports

　　C．providesupportiveevidence D．introducetheresearchprocess

　　31．Accordingtothescientists，whyistoomuchexercise harmful？___

　　A．Itmayinjuretheheartandarteries．

　　B．Itcanmakethebodytiredout．

　　C．Itwillbringmuchpressure．

　　D．Itconsumestoomuchenergy．

　　32．Whatcanbeinferredfromthetext？___

　　A．Noexerciseatallisthebestch