A debate can be challenging.Logical formLearned from51 sentences. A match can be challenging.Logical formLearned from50 sentences. Conditions may remain challenging.Logical formLearned from50 sentences. Holes can be challenging.Logical formLearned from50 sentences. Scenarios can be challenging.Logical formLearned from50 sentences. An environment may remain challenging.Logical formLearned from50 sentences. A feat can be challenging.Logical formLearned from49 sentences. (Lighting conditions) can be challenging.Logical formLearned from49 sentences. Courses can be challenging.Logical formLearned from49 sentences. Routes can be challenging.Logical formLearned from48 sentences. A program can be challenging.Logical formLearned from48 sentences. Runs can be challenging.Logical formLearned from47 sentences. Problems can be challenging.Logical formLearned from47 sentences. (Career opportunities) can be challenging.Logical formLearned from47 sentences. A layout can be challenging.Logical formLearned from47 sentences.