Times can be difficult.Logical formLearned from313 sentences. Weeks can be difficult.Logical formLearned from313 sentences. Environments can be difficult.Logical formLearned from313 sentences. A stretch can be difficult.Logical formLearned from311 sentences. Diagnosis can be difficult.Logical formLearned from308 sentences. Obstacles can be difficult.Logical formLearned from305 sentences. A piece can be difficult.Logical formLearned from298 sentences. A summer can be difficult.Logical formLearned from297 sentences. Positions can be difficult.Logical formLearned from292 sentences. A case can be difficult.Logical formLearned from286 sentences. (Weather conditions) can be difficult.Logical formLearned from284 sentences. An (operating environment) can be difficult.Logical formLearned from283 sentences. A world can be difficult.Logical formLearned from282 sentences. An exercise can be difficult.Logical formLearned from282 sentences. A (market environment) can be difficult.Logical formLearned from281 sentences.