A day can be rugged.Logical formLearned from9 sentences. A (frontier town) can be rugged.Logical formLearned from9 sentences. Defenders can be rugged.Logical formLearned from9 sentences. A (metal case) can be rugged.Logical formLearned from9 sentences. An engineering can be rugged.Logical formLearned from9 sentences. Volcanoes can be rugged.Logical formLearned from9 sentences. A (group activity) can be rugged.Logical formLearned from9 sentences. (Mountain trails) can be rugged.Logical formLearned from9 sentences. A (mountain man) can be rugged.Logical formLearned from9 sentences. A warrior can be rugged.Logical formLearned from9 sentences. An (aluminum case) can be rugged.Logical formLearned from9 sentences. Construction can be rugged.Logical formLearned from9 sentences. An option can be rugged.Logical formLearned from9 sentences. Standards can be rugged.Logical formLearned from9 sentences. A digital camera can be rugged.Logical formLearned from9 sentences.