I was solving a test on y vs. en, and there was a question:
Penses-tu à ton chien ?
- En penses-tu ?
- Y penses-tu ?
- Penses-en tu ?
- Penses-y tu ?
and I choose "Penses-y tu?" (I had no solid reason for that, but I remembered I saw verb-y formations before, so that “felt” right to me) but the right answer was "Y penses-tu?"
Can you explain to me why is "Y penses-tu?" a better choice?