Parallel Structure

Rules of Parallel Structure from Warriner’s English Composition and Grammar

Parallelism in sentence structure exists when two or more sentence elements of equal rank are similarly expressed. To create clarity and rhythm in a sentence, it is important to express similar ideas in similar grammatical forms. For example, pair an adjective with an adjective, a prepositional phrase with a prepositional phrase, and a clause with a clause. When you use the same grammatical form for similar ideas, you create parallel structure.
KINDS OF PARALLEL STRUCTURE
There are three sentence elements that commonly require parallel treatment: coordinated ideas, compared and contrasted ideas, and correlative constructions.
Coordinate Ideas
Coordinate ideas are equal in rank. They are joined by coordinate connectives. The coordinate connectives most often used in parallel structure and, but, or, and nor.
To express parallel ideas in the same grammatical form, pair one part of speech with the same part of speech, a verbal with the same kind of verbal, a phrase with a phrase, a clause with a clause. Do not pair unlike grammatical forms.
FAULTY          The committee studied all aspects of the problem: humane, political, and cost. [The adjectives humane and political are paired with the noun cost.]
PARALLEL      The committee studied all aspects of the problem: humane, political, and financial. [All three coordinate elements are adjectives.]
FAULTY          According to my teacher, my composition revealed exceptional creative ability but that I make too many spelling errors. [noun paired with clause]
PARALLEL      According to my teacher, my composition revealed exceptional creative ability but too many spelling errors. [noun paired with noun]
PARALLEL      According to my teacher, my composition revealed that I have exceptional creative ability but that I make too many spelling errors. [clause paired with clause]
FAULTY          Amanda’s favorite forms of exercise are swimming and to run. [gerund paired with infinitive]
PARALLEL      Amanda’s favorite forms of exercise are swimming and running. [gerund paired with gerund]
FAULTY          Derrick’s editorial shows his knowledge and that he is passionate about the subject. [noun paired with clause]
PARALLEL      Derrick’s editorial shows that he is knowledgeable about the subject and that he is passionate about it. [clause paired with clause]
Compared or Contrasted Ideas
FAULTY          Her novel was praised more for its style than for what it had to say.[noun paired with clause]
PARALLEL      Her novel was praised more for its style than for its ideas. [noun paired with noun]
FAULTY          Reading novels no longer interests me as much as to read poems. [gerund contrasted with infinitive]
PARALLEL      Reading novels no longer interests me as much as reading poems. [gerund contrasted with gerund]
FAULTY          In sports, enthusiasm is as important as that you have skill. [noun paired with clause]
PARALLEL      In sports, enthusiasm is as important as skill. [noun paired with noun]
Correlative Constructions

• To avoid awkwardness and confusion, place correlative conjunctions directly before the parallel terms.

Correlative constructions are formed with the correlative conjunctions both. . . and, either. . . or, neither. . . nor, not only. . . but (also).
FAULTY          Shawna considered both pursuing careers in law and in journalism.
PARALLEL      Shawna considered pursuing careers both in law and in journalism
FAULTY          Our choice of eight o’clock movies either was Slime or Return of the Insect People.
PARALLEL      Our choice of eight o’clock movies was either Slime or Return of the Insect People.
FAULTY          Mrs. Sayers is not only president of the National Bank but also of the Chamber of Commerce. [Not only precedes a noun, president, whereas but also precedes a prepositional phrase, of the Chamber of Commerce.]
PARALLEL      Mrs. Sayers is president not only of the National Bank but also of the Chamber of Commerce.
FAULTY        The team both felt the satisfaction of victory and the disappointment of defeat.
PARALLEL      The team felt both the satisfaction of victory and the disappointment of defeat.
FAULTY          At the gate they tried both persuasion and to force their way in. [noun paired with infinitive]
PARALLEL      At the gate they tried both persuasion and force. [noun paired with noun]
FAULTY          The new clerk soon proved herself to be not only capable but also a woman who could be trusted. [adjective paired with noun]
PARALLEL      The new clerk soon proved herself to be not only capable but also trustworthy. [adjective paired with adjective]
FAULTY          The medicine woman was revered not only for her healing abilities but also because she possessed wisdom. [prepositional phrase correlated with adverb clause]
PARALLEL      The medicine woman was revered not only for her healing abilities but also for her wisdom. [prepositional phrase s correlated with prepositional phrase]

• In parallel constructions, repeat an article, a preposition, or a pronoun whenever necessary to make the meaning clear. Note that the omission or inclusion of a word in the paired sentences below changes the meaning.

UNCLEAR      Before the meeting I talked with the secretary and treasurer. [The sentence may mean that I talked with one person who holds both offices.]
BETTER          Before the meeting I talked with the secretary and the treasurer. [This sentence indicates that I talked with two people.]
UNCLEAR      The weather was a greater handicap to the invading army than their enemy. [This sentence may mean that the invaders were handicapped more by the weather than by their enemy.]
BETTER          The weather was a greater handicap to the invading army than to their enemy. [This sentence means that the invaders had the greater handicap.]
UNCLEAR      I enjoyed the singing of the opera’s soprano more than the tenor. [The sentence may mean that I enjoyed the singing of the soprano more than the tenor enjoyed the singing of the soprano.]
BETTER          I enjoyed the singing of the opera’s soprano more than that of the tenor.  [This sentence means that I enjoyed the singing of the soprano more than I enjoyed the singing of the tenor.

GRAMMAR EXERCISES:  PARALLEL STRUCTURE

Correct the parallelism in each of the following sentences by putting parallel ideas into the same grammatical form or by inserting words that have been omitted.
1. Its large size, simple structure, and how readily available it is, make the common cockroach convenient to study.
2. Cockroaches have smooth, leathery skin; long, thin antennae; and they have a body that is thick and flat.
3. They are not only found in urban areas but in the tropics.
4. Cockroaches may be dark brown, pale brown, or of a green color that is delicate.
5. Cockroach eggs are laid in small cases, carried on the female body, and then they deposit them in hidden crevices.
6. A typical cockroach lives as a nymph for about a year, and as an adult its life lasts about half a year.
7. Cockroaches will eat anything, but they especially like sweet foods and foods that are starchy.
8. We might not only view the cockroach with disgust but also interest.
9. The cockroach both is the most primitive living winged insect and the most ancient fossil insect.
10. We have as much to learn from the cockroach’s evolution as there is to gain from extinguishing it.
11. Ms. Connor’s lectures are easier to comprehend than Ms. Moore.
12. A modern director’s interpretation of Hamlet is very different from a nineteenth-century director.
13. A dog’s ability to hear high-pitched sounds is much keener than humans.
14. How do your grades in English compare with science?
15. The biographical information in the encyclopedia is more detailed than the dictionary.
16. People have been more interested in reading the book than the movie version.
17. The view from the Chrysler Building is even more spectacular than the Empire State Building.
18. Some birds like to eat fruit as much as insects.
19. One of the accident victims suffered a broken arm, several broken  ribs, and one of her lungs was punctured.
20. She not only was industrious, but she could be depended on.
21. As we left the harbor, the radio weather report predicted gale-force winds, heavy rain, and that tides would be abnormally high.
22. To the unthinking person, war may be a romantic adventure, but a foolish and dirty business is the way the wise person regards it.
23. The unexpected cooperation of China was a greater surprise to Russia than the United States.
24. The skipper had a harsh voice, a weather beaten face, and was very stocky in build.
25. We were not sure that our request for a raise was fair or it would be granted.
26.Attention has been centered on the need for more teachers, adequate classrooms, and there isn’t enough new equipment.
27.This was a much harder assignment for me than Luis.
28.The ambassador did not know whether the President had sent for him or the Secretary of State.
29. Her friends not only were shocked by her failure but they felt a great disappointment.
30. The players were annoyed not so much by the decisions of the officials as the hostile crowd.
31. The company announced a bonus for all five-year employees and that deserving new employees would be given additional benefits.
32. Pioneers came with hopes of being happy and free and to make their fortunes in the new world.
33. All delegates to the convention were advised that on their return they would both have to make a written and oral report.