An opportunity can be challenging.Logical formLearned from259 sentences. Assignments can be challenging.Logical formLearned from252 sentences. Opportunities can be challenging.Logical formLearned from245 sentences. Areas can be challenging.Logical formLearned from243 sentences. An indoor environment can be challenging.Logical formLearned from235 sentences. Roles can be challenging.Logical formLearned from235 sentences. Experiences can be challenging.Logical formLearned from228 sentences. A job can be challenging.Logical formLearned from226 sentences. A world can be challenging.Logical formLearned from226 sentences. A total can be challenging.Logical formLearned from225 sentences. A (business environment) can be challenging.Logical formLearned from224 sentences. An area can be challenging.Logical formLearned from220 sentences. A task can be challenging.Logical formLearned from216 sentences. Years can be challenging.Logical formLearned from216 sentences. A game can be challenging.Logical formLearned from215 sentences.