Example sentences
nǐ你shì是nǎ哪guó国rén人？
What country are you from?
nǎ哪běn本shū书shì是nǐ你de的？
Which book is yours?
The story behind the character
哪
哪 means "which," and it takes a measure word before the noun: 哪个人 which person, 哪本书 which book. The one set phrase that skips it is 你是哪国人. Add 儿 and you get 哪儿, "where": 你去哪儿 where are you going. In casual speech that often comes out as 你去哪, and nobody will mishear you. English splits "which" and "where." Chinese points at the unknown spot with one word.