A person may stand at a bottom of stairs.Logical formLearned from9 sentences. Stairs can be slick.Logical formLearned from9 sentences. Stairs can be behind a male.Logical formLearned from9 sentences. Stairs may be replaced.Logical formLearned from9 sentences. A person may descend stairs.Logical formLearned from9 sentences. A female may bounce_down stairs.Logical formLearned from9 sentences. A person may fall_down (basement stairs).Logical formLearned from9 sentences. A person may run_down some flights of stairs.Logical formLearned from9 sentences. A male may yell_up stairs.Logical formLearned from9 sentences. Stairs may lead to a floor.Logical formLearned from9 sentences. Feet can be on stairs.Logical formLearned from9 sentences. Structural failure may pertain-to stairs.Logical formLearned from9 sentences. A person may climb_down stairs.Logical formLearned from9 sentences. Stairs can be at an end.Logical formLearned from9 sentences. A male may hear footsteps on stairs.Logical formLearned from9 sentences.