It's a common question used to inquire about someone's activity or reason for being in a particular place.
Here's a breakdown:
* Qué: What
* haces: do (informal, singular, present tense of "hacer")
* allí: there
Here are some examples of how you might use "qué haces allí?":
* "¿Qué haces allí en la cocina?" (What are you doing there in the kitchen?)
* "¿Qué haces allí en la esquina?" (What are you doing there on the corner?)
* "¿Qué haces allí sentado?" (What are you doing there sitting down?)
Let me know if you have any other Spanish phrases you'd like to translate!