The document discusses direct and indirect assertive sentences. It defines assertive sentences as simple statements that denote facts and end with a period. Direct speech reports the exact words spoken, while indirect speech conveys the full sense of what was said without using the exact words. The rules for changing direct assertive sentences to indirect include replacing demonstratives like 'this' and 'here' with 'that' and 'there' as well as changing temporal references like 'now' to 'then'. Examples are provided to illustrate applying these rules.