playground 一般指附属于学校内的活动场地。
Students gathered on the playground to watch the performance.
学生们聚集在操场上观看演出。
There is a big playground in our school.
我们学校有一个大操场。
gym 指不受天气影响的室内体育馆或运动场馆。
She looked at her timetable for the gym.
她正在看她的体育馆时间表。
I'm going to see my friend at the gym this evening.
我今晚要去体育馆看我的朋友。
stadium 指周围有看台的露天大型运动场。
The spectators trooped out of the stadium.
观众成群结队地走出体育场。
The stadium is oriented south and north.
那个体育场是南北走向。
