有读者朋友在我们的用户留言问，playground前用介词on还是in，我们查到手头的一本金盾出版社出版的《英语基础词汇用法词典》(周贞雄编著)，该书认为：表示在运动场上或在操场上，playground前既可用介词in也可用介词on，但以用in为普通，并举如下：

The children were all in [on] the playground. 孩子们都在操场上。

They are playing baseball in the playground. 他们在运动场上打棒球。

The sports meeting was held on the playground. 运动会在操场上举行。

我们也赞成这个观点，下面是本站编辑从不同权威词典查到的例句，可供参考：

■用in的例证：

1. He bullies all other little boys in the playground. 他在运动场上称王称霸，欺负其他小男孩。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

■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