This document appears to be a presentation about the proper use of "that" vs "which" in clauses. It provides:
1. Three quick rules for using "that" vs "which" - use "that" for restrictive clauses without commas, and use "which" for non-restrictive clauses with commas.
2. Three quick tips to identify restrictive vs non-restrictive clauses based on how removal of the clause affects meaning.
3. Examples and explanations of restrictive vs non-restrictive clauses, and when to use "that" vs "which" in different sentence structures.