见商务印书馆的《朗文当代高级英语辞典》bully词条
2.He was bashed up in the playground by some older boys.有几个年龄较大的男孩子在操场上对他动武。见商务印书馆的《牛津高阶英汉双解词典》(第四版)bash词条
3.children skipping in the playground在操场中跳绳的儿童,见商务印书馆的《牛津高阶英汉双解词典》(第四版)skip词条
4.The children were out in the playground letting off steam.那些孩子在操场上玩,宣泄过剩的精力。见商务印书馆的《牛津高阶英汉双解词典》(第四版)steam词条
5.The children were running about in the playground.孩子们在运动场上跑来跑去。见上海外教社的《朗文多功能分类词典》
6.There were children fighting in the playground.见《剑桥高级英语词典》(Cambridge Advanced Learner’s Dictionary)的fight词条
用on的例证:
The children ran out and played on the playground at recess.休息的时候孩子奔出来到操场上玩耍。见王文昌主编的《英语搭配大词典》
The boys chalked out goalposts on the playground wall.男孩子们在运动场的墙上用粉笔画上了球门柱。见商务印书馆的《牛津高阶英汉双解词典》(第四版)chalk词条(此句后中心词为wall,故用on)
另补充用at的例证:
He supervised the children at the playground.他看管在操场上的孩子们。见外研社的《当代美国英语学习词典》的supervise词条
综上所述,playground前用介词in比较权威。