VOA慢速英语:研究称美国高中体育运动反复发生脑震荡

athlete – n. someone who is trained or skilled in physical exercises, sports or games

practice – n. a repeated action or form of training

exposure – n. the fact or condition of being affected by something or experiencing something; the condition of being exposed to something

per – prep. with respect to every member of a group

recurrent – adj. happening or appearing again and again

mandatory – adj. required

associated – adj. joined together in a working relationship or alliance

evaluation – n. the act of judging the condition of someone or something in a careful and thoughtful way

access – n. ability to enter or pass from place to place