- The document discusses defining and non-defining relative clauses in English grammar. Defining relative clauses provide essential information about the noun they refer to, while non-defining relative clauses provide additional, non-essential information. - Defining relative clauses do not have commas and the relative pronoun can sometimes be omitted, while non-defining relative clauses have commas and the relative pronoun is never omitted or replaced with "that". - Examples are provided to illustrate the differences between defining and non-defining relative clauses.

1. RELATIVE CLAUSES

2. John is the man who works at the cinema. John, who works at the cinema, is also coming to the party. DEFINING RELATIVE CLAUSE NON-DEFINING RELATIVE CLAUSE