Grammar Rules and Usage (Chapter 13): Parts of speech (nouns, verbs, adjectives, etc.), Sentence structure (subject, predicate, objects), Tenses (present, past, future), Voice (active, passive), Mood (indicative, conditional, subjunctive). Common rules: Subject-verb agreement, pronoun-antecedent agreement, proper verb tense sequence. For accountants, grammar mastery ensures professional written communication. Exam tip: Master basic rules; understand exceptions; practice consistently.