It's similar, but I'm not convinced it's the same. "?אפשר ללכת" is asking permission, while "shall we go?" is a suggestion, like "?שנזוז?", "שנלך".
I wrote "Can I walk?" and it was marked wrong. Any ideas why? Or should it have been accepted?
With words like אפשר or מכיל, aside from intonation and punctuation marks, how can you tell if this is a question or a statement?