管不着

zhè shì wǒ men jiā shì nǐ guǎn bu zháo

这是我们家事，你管不着！

This is something within the family, and you have no right to interfere.

wǒ men zěn me guǎn bu zháo

我们怎么管不着？

Why shouldn't we interfere?

wǒ xiǎng chàng jiù chàng shuí yě guǎn bu zháo

我想唱就唱，谁也管不着。

I'll sing if I want to, and there's no law against it.