The document provides a lesson on adjective clauses and relative pronouns in English. It defines different types of relative pronouns used to combine two sentences based on the part of speech being referred to, such as subject, object of a verb, or object of a preposition. Examples are provided to illustrate the different relative pronouns that can be used, including who, whom, whose, which, and that. Exercises are included for students to practice combining sentences using relative clauses.