Treads may pertain-to stairs.Logical formLearned from4 sentences. A person may sweep stairs.Logical formLearned from4 sentences. A part can be stairs.Logical formLearned from4 sentences. Stairs can be double-time.Logical formLearned from4 sentences. A male may climb stairs to a flat.Logical formLearned from4 sentences. A male may be tripped on stairs.Logical formLearned from4 sentences. A male may force a chin stairs.Logical formLearned from4 sentences. A male may sleep under stairs.Logical formLearned from4 sentences. A female may trudge_up stairs.Logical formLearned from4 sentences. A person may sit_down stairs.Logical formLearned from4 sentences. A female may walk_up a flight of stairs.Logical formLearned from4 sentences. A person may race_up stairs.Logical formLearned from4 sentences. A person may stomp_up stairs.Logical formLearned from4 sentences. Stairs may pertain-to a train.Logical formLearned from4 sentences. A male may step_down stairs.Logical formLearned from4 sentences.