This document discusses adjectival clauses. It begins by defining an adjectival clause as a dependent clause that is used as an adjective within a sentence. It notes that adjectival clauses describe nouns and answer questions like "which one" or "what kind". The document then discusses the different types of relative pronouns that can introduce adjectival clauses and provides examples. It distinguishes between restrictive/essential adjectival clauses, which provide necessary information, and nonrestrictive/nonessential clauses, which provide extra information. The document concludes with exercises asking the reader to identify adjectival clauses in sentences and complete sentences with appropriate adjectival clauses.