Ensure parallel structure in lists, comparisons, and paired constructions.
Match the grammatical form of items in lists, comparisons, and paired constructions.
Core Idea
Items in a list, sides of a comparison, or elements joined by correlative conjunctions must use the same grammatical form. If two of three items are nouns and the third is a clause, the structure breaks.
Understanding
Parallel structure means matching grammatical forms when ideas are paired or listed. Your ear often catches these errors before your brain names them:
The program emphasizes reading, writing, and how to think critically.
Two gerunds and a clause — that's not parallel. Fix: reading, writing, and thinking critically.
Parallelism shows up in three SAT patterns:
Lists: Every item must be the same part of speech.
- Nouns: "courage, integrity, and perseverance"
- Gerunds: "running, swimming, and cycling"
- Infinitives: "to read, to write, and to speak"
Comparisons: What you compare must be grammatically equivalent.
- Wrong: "The cost of living in Tokyo is higher than New York" (compares cost to a city)
- Right: "...higher than the cost of living in New York" (compares cost to cost)
Correlative conjunctions: both...and, either...or, neither...nor, not only...but also. Whatever follows the first word must grammatically match whatever follows the second.
- "She is both talented and hardworking" (adjective, adjective) ✓
- "She both is talented and hardworking" (verb + adjective, adjective) ✗
Step by Step
- Identify the parallel structure: is it a list, a comparison, or a paired construction (both/and, either/or, etc.)?
- For lists: check that every item uses the same grammatical form (all nouns, all gerunds, all infinitives, etc.).
- For comparisons: make sure you're comparing equivalent things (cost to cost, method to method — not cost to city).
- For correlative conjunctions: check that the element after each conjunction is the same part of speech.
- Pick the answer that makes all items grammatically consistent.
Misconceptions
- Thinking parallelism only applies to lists. It also applies to comparisons ("more than"), correlative conjunctions ("not only...but also"), and any structure that pairs ideas.
- Matching meaning but not form. "She likes hiking, swimming, and to run" — all three are activities, but "to run" breaks the gerund pattern.
- Ignoring the words before the list items. "The plan involves identifying problems, developing solutions, and implementation" — the gerund pattern set by "identifying" and "developing" must continue with "implementing," not the noun "implementation."
Worked Example
The robotics competition requires participants to design a functional prototype, __________ a detailed engineering report, and present their findings to a panel of judges.
Select an answer to see the explanation