Fill in the Blanks Fill in the Blanks: Defining and Non-Defining Relative ClausesOnline version Test your knowledge of relative clauses by filling in the blanks with the appropriate type: defining or non-defining. by Nathalia Garcia Rojas 1 essential information Defining additional information commas core meaning necessary relative clauses provide about the noun they refer to , while non - defining relative clauses provide . Defining clauses are not separated by and are for the sentence's meaning . Non - defining clauses are separated by commas and can be omitted without changing the of the sentence .