D
Sciencecan'texplainthepowerofpets,butmanystudieshaveshownthatthecompanyofpetscanhelplowerbloodpressure(血压)andraisechancesofrecoveringfromaheartattack,reducelonelinessandspreadall-roundgoodcheer.Anyownerwilltallyouhowmuchjoyapetbrings.Forsome,ananimalprovidesmorecomfortthanahusband/wife.A2002studybyKarenAllenoftheStateUniversityofNewYorkmeasuredstr ess(紧张)levelsandbloodpressureinpeople-halfofthempetowners–whiletheyperformed5minutesofmentalarithmetic(算术)orheldahandinicewater.Subjectscompletedthetasksalone,withahusband/wife,aclosefriendorwithapet.Peoplewithpetsdiditbest.Thosetestedwiththeiranimalfriendshadsmallerchangeinbloodpressureandreturnedmostquicklytobaselineheartr ates.Withpetsintheroom,peoplealsomadefewermathmistakesthanwhendoinginfrontofothercompanions.Itseemspeoplefeelmorerelaxed(放松)aroundpets,saysAllen,whothinksitmaybebecausepetsdon'tjudge.Astudyreportedlastfallsuggeststhathavingapetd ognotonlyraisesyourspiritsbutmayalsohaveaneffectonyoureatinghabits.ResearchersatNorthwesternMemorialHospitalspentayearstudying36fatpeopleandtheirequallyfatd ogsondiet-and-exerciseprograms;aseparategroupof56peoplewithoutpetswereputonadietprogram.Onaverage,peoplelostaboutI1pounds,or5%oftheirbodyweight.Theirdogsdidevenbetter,losinganaverageof12pounds,morethan15%oftheirbodyweight.Dogownersdidn'tloseanymoreweightthanthosewithoutd ogsbut,sayresearchers,gotmoreexerciseoverall-mostlywiththeirdogs-andfounditworthdoing.
67．Whatd oesthetextmainlydiscuss?
A．Whatpetsbringtotheirowners.
B．Howpetshelppeoplecalmdown.
C．People'sopinionsofkeepingpets.
D．Pet'svalueinmedicalresearch.
正确答案：A
