It's a rule that dates back to the playgroud: Once you start dissing a boy's mother, things are going to get ugly.

这是可以追溯到很久的游戏规则：一旦你开始对男孩的母亲不敬的话，事情将会变得令人厌恶。

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In front of the teaching building is a large playground. After class, we are running in the playgroud, and play, there are many trees on the playground.

在教学楼前面有一个大操场。下课后，我们在操场上跑步，打球，玩耍，操场上还有许多树。

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