1. The document discusses different types of relative clauses including defining and non-defining relative clauses. It provides examples of relative clauses using who, whom, which, that, whose, why, where, when. 2. Relative pronouns are used to join two sentences together where the second sentence provides more information about the noun mentioned in the first sentence. Different relative pronouns are used depending on whether the relative clause refers to a person or thing. 3. The document provides examples of relative clauses and practice questions for the reader to test their understanding of using relative pronouns correctly in sentences.