Alice E. M. Underwood
Parallel sentence elements in grammar are just like parallel lines in geometry: they face the same direction and never meet.
More precisely, in grammar, it’s less about meeting and more about balance. Parallelism in grammar is defined as two or more phrases or clauses in a sentence that have the same grammatical structure.
The Why
A sentence with parallel construction makes your writing effective, classy, and certain to impress anyone who reads your stuff.
The How
Here’s a handy trick for testing parallelism: rewrite the sentence for each element that should be parallel. For example:
A sentence with parallel construction makes your writing effective. A sentence with parallel construction makes your writing classy. A sentence with parallel construction makes your writing certain to impress anyone who reads your stuff.
Effective, classy, and certain are all adjectives. Even though “certain to impress anyone who reads your stuff” is a mouthful compared to the other two, each sentence element is the same part of speech. That makes the sentence balanced, and therefore, parallel. See More . . .