Parallel construction, also called parallel structure or parallelism, shows that two or more ideas—in comparisons, lists, and compound elements—are equally important by stating them in the same grammatical pattern. Parallelism brings precision, elegance, and symmetry to what you write. The following example is from the Chicago Manual of Style, 13th Edition:
I came; I saw; I conquered.
—Julius Caesar
Using three simple verbs to list the things he did, Caesar makes coming, seeing, and conquering equal in importance, and implies that, for him, conquering was as easy as coming and seeing.
There are a number of situations that require you to use parallel structure. They are:
- Neither A nor B
- Either A or B
- Both A and B
- Not A but B
- Not only A but also B
In parallel construction, the words in the list must be in the same grammatical form, i.e., noun lined up with noun, verb line up with verb, and phrase lined up with phrase.
Examples:
Incorrect: In counseling, I think both talking and to listen are important.
Correct: In counseling, I think both talking and listening are important.
Incorrect: The conference is neither a long one nor expensive.
Correct: The conference is neither long nor expensive.