This document discusses the different types and structures of adjective clauses. It explains that when, where, and which+preposition can be used in nonrestrictive clauses, while that or that+preposition can also be used in restrictive clauses. It provides examples of simple and complex sentences using restrictive and nonrestrictive clauses. The document also discusses the use of expressions like "one of" and verbs forms in adjective clauses, noting they should agree with the noun being modified.