Inmanysports，physicalcontactispartofthegame.Butwhenathl...
问题详情：Inmanysports，physicalcontactispartofthegame.Butwhenathleteshittheirheads，thehitcancauseconcussions（脑震荡）.Concussionshavelongbeenaconcernforprofessionalathletes，butthey'vebecomemorecommonamongyou...