Parallel structure means matching grammatical form in a list or comparison—verbs with verbs, nouns with nouns—so the ACT can spot a broken series instantly. When choices differ only in form, pick the pattern that matches the rest of the list.
What the ACT tests
Lists, paired items, and correlative conjunctions (both/and, either/or, not only/but also) must use the same structure. Part of grammar rules on ACT English.
Examples
- She likes hiking, swimming, and to bike. → fix to three -ing forms or three infinitives consistently.
- Not only fast but also accurately. → adverb pairs: fast and accurately mismatch; use accurate or quickly to match.
How to solve fast
- Find the list or correlative pair in the sentence.
- Label the form of the first item (verb, noun, adjective).
- Eliminate choices that break the pattern.
Related rules
Parallelism shows up with subject-verb agreement and concision—fix form first, then check if DELETE is still best.
Start practicing
Start with a free diagnostic, then drill your weak spots with 15-question quizzes and track how you're doing across Reading, English, and Math. Compare plans whenever you're ready to go further.
This article offers general ACT prep guidance. The ACT can change from year to year, including its format, scoring, policies, test dates, and fees, so always confirm the latest details on the official ACT website at act.org before you make decisions. ACT® is a registered trademark of ACT, Inc. thirty-six is not affiliated with, endorsed by, or sponsored by ACT.