Why should he go abroad? - Keep your nose out of it.

他为什么必须出国呢？ - 别多管闲事。

We believed in responsibility and keeping your nose out of other people’s business.

我们相信责任，让你的鼻子远离别人的生意。

If you'd kept your nose out of my business!

如果你别管我的闲事！

“But we're not telling you what was in there, so keep your noses out if you know what's good for you, ” said a Gringotts spokesgoblin this afternoon.

金库中究竟存放何物，无可奉告，请勿干预此事为好。