I'm just minding my own business. 我正在做自己的工作。

　　Mind your P's and Q's! 注意你的言行举止！

　　I'll thank you to mind your own business. 如果你不干涉别人的事情，我就特别感激了。

　　Why can't you mind your own business? What is your problem? 你为什么要干涉别人的事情？你到底有什么问题？

　　I think I'm going to ask them what they're talking about. 我觉得我应该问问他们在聊些什么。

　　Why don't you mind your own business? 你怎么不管管你自己的事情？