The document defines parallel structure as using the same pattern of words to show that two or more ideas have equal importance. It provides three rules for using parallel structure: 1) elements in a parallel list must be joined with conjunctions and be grammatically similar, 2) structures beginning with clauses must continue using those clauses, and 3) lists must use the same verb tense. Examples are given to illustrate correct and incorrect uses of parallel structure. Exercises at the end provide opportunities to practice applying the rules.