Which? nào after the noun

Nào means "which", and it comes after the noun: Chị ở quận nào? Which district do you live in? Anh muốn cái áo nào? Which shirt do you want? Like other question words, it stands where the answer will go: Chị ở quận Ba.

Use nào when the answer is one from a set: these shirts, the districts of a city, the countries of the world. Người nước nào? asks which country someone is from. With time words it asks when: Hôm nào anh rảnh? Which day are you free?

Keep the counting word with nào: cái nào? asks "which one?" about things, con nào? about animals. The answer can drop the noun but keeps the counting word: Cái này. This one. Cái màu đỏ. The red one.

Gì after a noun usually asks what kind, open-ended: Em thích màu gì? What color do you like? Nào points at choosing one: Em lấy màu nào? Which color will you take? Often both sound fine.

At the end of a request, nào isn't a question: it means "come on" or "let's": Đi nào! Let's go!