(Mountain ridges) can be rugged.Logical formLearned from4 sentences. Variety can be rugged.Logical formLearned from4 sentences. Portable computers can be rugged.Logical formLearned from4 sentences. A planet can be rugged.Logical formLearned from4 sentences. A (magnesium alloy) can be rugged.Logical formLearned from4 sentences. An end can be rugged.Logical formLearned from4 sentences. Views can be rugged.Logical formLearned from4 sentences. Runs can be rugged.Logical formLearned from4 sentences. A child can be rugged.Logical formLearned from4 sentences. A family can be rugged.Logical formLearned from4 sentences. (Rock outcroppings) can be rugged.Logical formLearned from4 sentences. Pinnacles can be rugged.Logical formLearned from4 sentences. Conditions can be rugged.Logical formLearned from4 sentences. An interior can be rugged.Logical formLearned from4 sentences. Roles can be rugged.Logical formLearned from4 sentences.