A challenge can be for a person.Logical formLearned from1 978 sentences. A challenge may pertain-to a country.Logical formLearned from1 938 sentences. Challenges may pertain-to a male.Logical formLearned from1 881 sentences. Challenges may pertain-to a person.Logical formLearned from1 768 sentences. A set can be constituted-of-or-filled-with challenges.Logical formLearned from1 765 sentences. Challenges can be tough.Logical formLearned from1 719 sentences. Challenges can be physical.Logical formLearned from1 698 sentences. Challenges can be complex.Logical formLearned from1 515 sentences. A challenge can be stiff.Logical formLearned from1 494 sentences. A series can be constituted-of-or-filled-with challenges.Logical formLearned from1 430 sentences. Persons may face challenges.Logical formLearned from1 353 sentences. Part may pertain-to a challenge.Logical formLearned from1 324 sentences. A challenge can be for persons.Logical formLearned from1 308 sentences. A challenge can be personal.Logical formLearned from1 302 sentences. A challenge may pertain-to a week.Logical formLearned from1 286 sentences.