Here's the breakdown:
* Quel: Used before masculine singular nouns.
* Quelle: Used before feminine singular nouns.
Examples:
* Quel livre lis-tu? (What book are you reading?)
* Quelle couleur préfères-tu? (Which color do you prefer?)
Important:
* "Quel" and "Quelle" change form depending on the noun's gender and number:
* Quels: Used before masculine plural nouns.
* Quelles: Used before feminine plural nouns.
Let me know if you'd like to see more examples or have any further questions!