An (operating environment) may remain difficult.Logical formLearned from18 sentences. Shapes can be difficult.Logical formLearned from18 sentences. A crisis can be difficult.Logical formLearned from17 sentences. A manner can be difficult.Logical formLearned from17 sentences. A film can be difficult.Logical formLearned from17 sentences. Computations can be difficult.Logical formLearned from17 sentences. Transmission can be difficult.Logical formLearned from17 sentences. Contexts can be difficult.Logical formLearned from17 sentences. Portfolios can be difficult.Logical formLearned from17 sentences. Settlement can be difficult.Logical formLearned from17 sentences. A capture can be difficult.Logical formLearned from17 sentences. Placement can be difficult.Logical formLearned from17 sentences. A (learning curve) can be difficult.Logical formLearned from17 sentences. A theme can be difficult.Logical formLearned from17 sentences. A production can be difficult.Logical formLearned from17 sentences.