This document defines parallelism and provides rules for using parallel structure in sentences. It states that parallelism is arranging sentences so that their components are balanced, similar in construction, sound, or meaning. It then lists four rules for parallel structure: 1) parts serving a similar function should be grammatically similar, 2) avoid shifting pronouns when referring to the same person or people, 3) avoid shifting verb tenses when events occur at the same time, and 4) avoid shifting between active and passive voice when the same subject is involved. Examples are given to illustrate parallel and nonparallel structures.