The ages of the athletes who will take part in the Asian Games are 21 ________．
A.on averageB.in commonC.in generalD.as usual在线课程A
句意为“参加这次亚运会的运动员平均年龄是21岁”。on average平均；in common共同，共有；in general总的来说；as usual像往常一样。