题目内容：
阅读短文，并按照题目要求用英语回答题。Bornin1949,DianaNyadtookanearlyinterestinswimmingasasportandwasaFloridaStateHighSchoolswimmingchampion.Likemanyyoungathletes,shehadOlympicdreams,butaseriousillnesskeptherfromcompetingintheGames.Thedisappointmentdidn’tstopherfromgoingforward.Instead,shebecameinterestedinmarathonswimming.Abrilliantathlete,shewaswell-conditionedforspendinglongperiodsoftimeinthewater.Asalong-distanceswimmer,shewouldcompeteagainstherselfandtheobstaclespresentedbydistance,danger,cold,andexhaustion.
FortenyearsNyaddevotedherselftobecomingoneoftheworld’sbestlong-distanceswimmers.In1970,sheswamaten-milemarathoninLakeOntario,settingthewomen’srecordforthecourse.In1972shesetanotherrecordbyswimming102.5milesfromanislandintheBahamastothecoastofFlorida.ThenshebrokeathirdrecordwhenswimmingaroundManhattanIslandin1975.
NyadattemptedtoswimthedistancebetweenFloridaandCubain1978.Thoughthespanofwaterislessthan100mileswide,itisroughanddangerous.Afterbattlingthewaterfortwodays,shehadtogiveforthesakeofherownhealthandsafety.Evenso,sheimpressedtheworldwithhercourageandstrongdesiretosucceed.ForNyadherstrengthofpurposewasjustasimportantasreadingCuba.Thatishowshedefinedsuccess.Itdidnotmatterthatherswimcameupshort;shebelievedshehadtouchedtheothershore.
WhenNyadendedhercareerasaswimmer,shecontinuedtotrynewthings---travellingtheworldasareporter,writingbooksandgivingpublicspeechesaboutherlife.DianaNyadworkstoinspireothers,justasshedidwhensheswamthewatersoftheworld.
WhatpreventedNyadfromtakingpartintheOlympicGames?(Nomorethan5words)
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