Stairs can be hidden.Logical formLearned from9 sentences. Markings can be on stairs.Logical formLearned from9 sentences. A person may go stairs.Logical formLearned from9 sentences. Part may pertain-to stairs.Logical formLearned from9 sentences. Stairs may be hited.Logical formLearned from9 sentences. A female may fall from stairs.Logical formLearned from9 sentences. Stairs may be removed.Logical formLearned from9 sentences. A male may see stairs.Logical formLearned from9 sentences. Persons may climb some stairs.Logical formLearned from9 sentences. Stairs can be in a house.Logical formLearned from9 sentences. A photograph can be from stairs.Logical formLearned from9 sentences. Stairs can be cool.Logical formLearned from9 sentences. Stairs can be slippery.Logical formLearned from9 sentences. A male may walk_up a flight of stairs.Logical formLearned from9 sentences. A male may run_down some flights of stairs.Logical formLearned from9 sentences.