The document discusses different types of relative pronouns and clauses in English grammar including:
- Defining and non-defining relative clauses using who, whom, whose, that, which
- Possessive relative clauses using whose
- Adverbial relative clauses using when, where, why
- Special uses of relative pronouns like but
- Cleft sentences which focus elements of a sentence by placing them after an "it" subject and form of be.