A piece can be difficult.Logical formLearned from29 sentences. A finish can be difficult.Logical formLearned from29 sentences. A movement can be difficult.Logical formLearned from29 sentences. Some hours can be difficult.Logical formLearned from29 sentences. Crossings can be difficult.Logical formLearned from29 sentences. Environmental problems can be difficult.Logical formLearned from29 sentences. A model can be difficult.Logical formLearned from29 sentences. A search may prove difficult.Logical formLearned from29 sentences. (Security issues) can be difficult.Logical formLearned from29 sentences. Details can be difficult.Logical formLearned from29 sentences. Markets can be difficult.Logical formLearned from29 sentences. Claims can be difficult.Logical formLearned from29 sentences. A pain can be difficult.Logical formLearned from29 sentences. (Driving conditions) can be difficult.Logical formLearned from29 sentences. A (consumer environment) can be difficult.Logical formLearned from29 sentences.