A hardness may be exhibited in resistance to scratching.Logical formLearned from1 sentences. A cat may mark a territory by scratching.Logical formLearned from1 sentences. A paw may be used without scratching.Logical formLearned from1 sentences. A person may scratch.Logical formLearned from1 sentences. A cat may scratch furniture.Logical formLearned from1 sentences. Cells may be scratched with a file.Logical formLearned from1 sentences. Graffiti may be scratched on a (cave wall).Logical formLearned from1 sentences.