Food is scarce for these people, you shouldn't turn your nose up at it.

这些人缺粮，你不该嫌东道西的。

You may turn your nose up at working as a janitor – cleaning toilets – because you think you are better than that.

你可能会对清洁厕所的工作嗤之以鼻，因为你认为自己比那更好。