Here's the answer:
“?volverás antes o después de la cena?”
Watch a real native speaker say it:
Here's how it sounds in a textbook:
You could also say:
- ?volverán antes o después de la cena?
- ?volveréis antes o después de la cena?
Fun fact: the hundreds of thousands of people learning Spanish with Memrise get this phrase correct 96.32% of the time!