Zippers can be rugged.Logical formLearned from6 sentences. Fields can be rugged.Logical formLearned from6 sentences. An (ocean floor) may be marked by rugged mountains.Logical formLearned from6 sentences. A division can be rugged.Logical formLearned from6 sentences. Snowy mountains can be rugged.Logical formLearned from6 sentences. A border can be rugged.Logical formLearned from6 sentences. A border may straddle rugged mountains.Logical formLearned from6 sentences. A rubber can be rugged.Logical formLearned from6 sentences. Pockets can be rugged.Logical formLearned from6 sentences. A (desert base) can be rugged.Logical formLearned from6 sentences. An industrial town can be rugged.Logical formLearned from6 sentences. Peacekeepers may patroll rugged mountains with a country.Logical formLearned from6 sentences. A march can be through a rugged mountain.Logical formLearned from6 sentences. Rebels can be in rugged mountains of a southeast.Logical formLearned from6 sentences. Pickups can be rugged.Logical formLearned from6 sentences.