Why is " can I see the menu before please" wrong?
I agree, it should be accepted, it makes as much sense as "can i see the menu first"...
Before what? The preposition needs an object.
Doesn't "eu" sound weird in this case, since it's a question? Is "posso ver o menu antes, por favor?" correct?
It's true that this question is more common without "eu", but it's not weird at all.