context: Four people in emergency suits and helmets spray water from behind a cement wall.
hypothesis: We believe that fire fighters are battling a fire safely behind a cement wall.
valid_hypothesis: We believe that fire fighters are battling a fire safely behind a cement wall.
invalid_hypothesis: There is little chance that fire fighters are battling a fire safely behind a cement wall.
hypothesis_assertion: Fire fighters are battling a fire safely behind a cement wall.