playground用in还是on还是at？united states是什么意思？

1.The girls were skipping in the playground.姑娘们在操场上跳绳。男孩们在操场上讲威尔士语是要吃鞭子的。3.Attitudes learned at home carry over into the playground.家里养成的作风会表现在学校的运动场上。

playground用in还是on还是at？

1.The girls were skipping in the playground.姑娘们在操场上跳绳。

2.In Wales in the same era, boys were caned for speaking Welsh in the playground.在同一时期的威尔士，男孩们在操场上讲威尔士语是要吃鞭子的。

3.Attitudes learned at home carry over into the playground.家里养成的作风会表现在学校的运动场上。

united states是什么意思？

united states　英 [ju'naɪtɪd s'teɪts] 　 　 美 [ju'naɪtɪd s'teɪts] 　 　n. 美国He went on a speaking tour of the United States.他去美国作巡回演讲。