A muscle can be stiff.Logical formLearned from6 sentences. A solver can be stiff.Logical formLearned from6 sentences. A nylon can be stiff.Logical formLearned from6 sentences. Fines can be stiff.Logical formLearned from6 sentences. Waves can be stiff.Logical formLearned from6 sentences. Teeth can be stiff.Logical formLearned from6 sentences. A face may go stiff.Logical formLearned from6 sentences. Folds can be stiff.Logical formLearned from6 sentences. A mess can be stiff.Logical formLearned from6 sentences. Conventions can be stiff.Logical formLearned from6 sentences. A stiff upper lip may undergo a softening.Logical formLearned from6 sentences. (Economic sanctions) can be stiff.Logical formLearned from6 sentences. A case can be stiff.Logical formLearned from6 sentences. An (economic embargo) can be stiff.Logical formLearned from6 sentences. A country may look stiff.Logical formLearned from6 sentences.