Parallel structure will help improve the clarity and efficiency of your writing. All of the items in a series should use the same form, regardless of whether or not they are words, phrases, or clauses. This cartoon, from Grammar Comics: Sentence Problems, helps explain the various problems that can result with parallel structure.
Incorrect: Chloe is cute, intelligent, and knows a lot of good jokes.
Cute and intelligent are both adjectives. Knows is a verb. Therefore, to revise this sentence to improve the parallel structure you would write:
Chloe is cute, intelligent, and funny.
Or, you could do this:
Chloe has a terrific smile, a well-developed intelligence, and a good sense of humor.
But you don’t want to do this:
Incorrect: Chloe has a terrific smile, intelligence, and a good sense of humor.
Notice that the only part of the series without an a is intelligence. If each of the other two parts begins with a, then the third part must as well.
Avoid mixing verb forms as well:
Incorrect: Chloe likes playing tennis, watching movies, or to ride her bike.
Correct: Chloe likes to play tennis, to watch movies, or to ride her bike.
Or: Chloe likes to play tennis, watch movies, or ride her bike.
Be careful with long phrases as well:
Incorrect: Mr. Hernandez told his students that they should do their homework, that they study for their vocabulary test, and to read some articles.
Correct: Mr. Hernandez told his students that they should do their homework, study for their vocabulary test, and read some articles.
For more entertaining comics on common sentence problems, please check out Grammar Comics: Sentence Problems.
The author of this article is David Rickert, who leads parallel lives as a cartoonist and teacher. When not creating comics out of thin air, David teaches high school English Language Arts in Columbus, Ohio. His witty and engaging cartoons turn abstract and complicated concepts into concrete and concise images to embed content into our long term memories (credit petter). Let’s face it: he makes boring topics entertaining. Check out his Grammar Comics and more resources to bring life to your ELA instruction: Grammar, Usage, and Mechanics.