An old man walking a ferrett through the street on a leash .
It is almost certain that a young woman is walking next to a dog that is n't on a leash .
It is impossible that a young woman is walking next to a dog that is n't on a leash .
It is almost certain that a young woman is walking next to a dog that is n't on a leash .
A young woman is walking next to a dog that is n't on a leash .