In a city in front of a subway , a man skateboards down a stairway as two older ladies sitting on a bench watch him .
It is probably the case that a man skateboards down a stairway , while performing .
It is probably not the case that a man skateboards down a stairway , while performing .
It is probably the case that a man skateboards down a stairway , while performing .
a man skateboards down a stairway , while performing .