A book can be on a subject.Logical formLearned from737 sentences. A subject can be constituted-of-or-filled-with controversy.Logical formLearned from734 sentences. A sensitivity may pertain-to a subject.Logical formLearned from712 sentences. A male may change a subject.Logical formLearned from705 sentences. Subjects can be constituted-of-or-filled-with interest.Logical formLearned from702 sentences. Views can be on a subject.Logical formLearned from678 sentences. A subject may pertain-to a message.Logical formLearned from677 sentences. A subject can be serious.Logical formLearned from669 sentences. Thoughts can be on a subject.Logical formLearned from661 sentences. A nature may pertain-to a subject.Logical formLearned from658 sentences. A subject may pertain-to an investigation.Logical formLearned from657 sentences. Subjects can be taboo.Logical formLearned from646 sentences. Subjects can be difficult.Logical formLearned from638 sentences. A subject can be favourite.Logical formLearned from630 sentences. A person may change a subject.Logical formLearned from627 sentences.