concentrations/ˌkɑːn.sənˈtreɪ.ʃən/名词专注，专心The noise outside made concentration difficult.外面吵得我难以集中注意力。集中；聚集；汇集a concentration of one part per million百万分之一的浓度配对纸牌游戏想跟读，去练习
