Lotsofstudentsknowwhatamarathon(马拉松赛跑)is,butperhapsthey...
问题详情：Lotsofstudentsknowwhatamarathon(马拉松赛跑)is,butperhapstheydon’tknowwhatatriathlonis.Thetriathlonisasportthathasthreeparts-swimming,bicyclingandrunning.Itisnotaneasysport,butamannamedJoeSalt...