simplesat

Grammar rules

Parallel Structure on the SAT: Make the List Match

Updated July 7, 2026

How does SAT parallel structure work?

You read the sentence, nothing sounds obviously broken, and you still miss the question. On the SAT, one common reason is parallel structure: when a sentence lists or pairs things, every item has to share the same grammatical form, and the wrong answer is almost always the one item that quietly switched forms. The rule is mechanical, which means you can catch it every time with a ten-second check instead of trusting your ear.

The Matching Test: strip every item to its bare form

Here is the whole method, and it is the only one you need for this rule. When you see a list or a pair, do this:

  1. Write each item on its own line.
  2. Strip it down to its bare grammatical form and name that form: gerund (the -ing form used as a noun), infinitive (to plus a verb), plain noun, past-tense verb, adjective.
  3. Confirm every item wears the exact same label. The one that breaks the pattern is the error, even if it reads fine on its own.

We call this the Matching Test. It works because parallelism is not about meaning, it is about form. Each item can be perfectly correct in isolation and the sentence still fails.

The internship taught her to code, to pitch, and managing a budget.

Stack the items after "taught her": to code (infinitive), to pitch (infinitive), managing (gerund). Two match, one does not. Managing is the leak. Fix it to match the pattern the list already set: to manage a budget. Or flip all three to gerunds: coding, pitching, and managing. Either is parallel. What you cannot do is mix.

That is the entire rule. The rest of this page is the three places the SAT hides the mismatch and the traps that make the odd item hard to see.

Series of three: where the last item drifts

Most parallelism questions live inside a list of three or more items. The danger is structural: by the time your eye reaches the final item, it has already read two matching forms and relaxed, so a switch at the end slips past. Test writers know this, so the break is usually the last item, not the first.

The coach wanted players who were fast, disciplined, and who thought clearly under pressure.

Items after "players": fast (adjective), disciplined (adjective), who thought clearly under pressure (a relative clause). The first two are one-word descriptions; the third is a whole clause. Not parallel. Fix it by matching form: fast, disciplined, and level-headed. Three adjectives, clean.

A related question rides along with the list: the serial comma. In a list of three or more items, a comma goes before the "and" that introduces the final item (fast, disciplined, and level-headed). A list of only two items joined by "and" takes no comma at all (fast and disciplined, never fast, and disciplined). The trap is miscounting the items. If one "item" is itself a compound, like rest and recovery or bread and butter, it counts as one entry, not two, so do not let its internal "and" fool you into adding a comma. Count the real items first, then apply the comma rule. The full comma logic lives in the comma rules guide.

Paired connectives: both sides must match

Parallelism is not only for lists. Certain paired words, called correlative conjunctions, demand matching forms on each side:

  • not only ... but also
  • either ... or
  • neither ... nor
  • both ... and

The rule: whatever grammatical form follows the first half must follow the second half. The two pieces should be swappable in structure.

She wanted not only to win the race but also the respect of her teammates.

After not only comes to win the race (an infinitive phrase). After but also comes the respect of her teammates (a plain noun phrase). Mismatch. The clean fix moves the connective so both halves carry the same form: She wanted not only to win the race but also to earn the respect of her teammates. Now both sides are infinitive phrases, and the pair balances.

Quick self-check for correlatives: read the word right after the first connective and the word right after the second. If one is a verb and the other is a noun, you have a break.

Verb-form parallelism: shared helpers, shared form

When several verbs share one subject or one helping verb, they all inherit that verb's form. Drop the helper back in front of each item and the odd one becomes obvious.

The report will summarize the data, highlight the trend, and to recommend a fix.

All three verbs run under will. Say it out with the helper attached to each: will summarize, will highlight, will to recommend. The third one collapses. Fix: summarize the data, highlight the trend, and recommend a fix. This is close cousin to keeping tenses consistent across a sentence, covered in the verb tense guide, and it is one of the recurring defects the form, structure, and sense questions are built to test.

The traps that hide the mismatch

  • The odd item at the end. As above, the break usually sits in the last item, where your attention has drifted. Read the final item against the first with fresh eyes, not against the item just before it.
  • Each item reads fine alone. This is what beats the ear. Managing a budget is a perfectly good phrase; it is only wrong because the list around it chose infinitives. Do not ask "does this item sound okay?" Ask "does this item match the others?"
  • The comparison cousin. Parallelism has a sibling rule: comparisons must pit like against like (her novels are longer than Dickens's, not longer than Dickens). Same instinct, different question type, handled in the illogical comparisons guide.
  • Anchoring on the smooth choice. If you read the four answer choices first and pick the one that flows, you are letting the choices decide for you. That is anchoring, and here it is fatal, because the trap answer is engineered to sound smooth. Decide the required form from the sentence before you look. The punctuation and agreement checks in the SAT grammar rules pillar all work this same mechanical way.

The drill: run the Matching Test on yourself

Here is a self-test you can run today. On your next practice set, every time you hit an "and," "or," or a "not only ... but also," stop and do the three steps: stack the items in a column, label each one's form, and box the outlier. Do not answer from feel. Do it for ten list questions.

Then check your misses. If you were choosing the smooth-sounding option instead of the matching one, your leak is process, not knowledge, and the fix is the habit above: match, do not listen. Points lost to a rule you actually know are the purest kind of wasted points, and this one is fully preventable.

Practice it now: the free simplesat grammar drill runs parallel-structure items with per-question feedback that names the exact form that broke. No signup, works as a guest.

Frequently asked questions

What breaks parallelism?

Mixing grammatical forms inside a list or a paired construction. If two items in a series are gerunds and the third is an infinitive, or if the phrase after "not only" is a verb and the phrase after "but also" is a noun, parallelism breaks. Each item can be correct on its own; the error is the mismatch, not the item.

Is mixing a gerund and an infinitive really wrong?

Inside one parallel series, yes. She likes running, swimming, and to bike is not parallel because to bike switches to an infinitive. Pick one form and hold it across every item: running, swimming, and biking, or to run, to swim, and to bike.

Do I put a comma before "and" in a list?

In a list of three or more items, yes: the serial comma goes before the final "and" (speed, accuracy, and reliability). In a list of only two items, no comma at all (speed and accuracy). Watch for compound items like bread and butter, which count as a single entry, so their internal "and" does not take a comma. Count the true items first.

Does parallel structure only apply to lists?

No. It also governs paired connectives (either ... or, both ... and), verbs sharing one helper, and comparisons of like things. Any time a sentence sets up two or more parts in the same slot, those parts have to share a form. The Matching Test catches all of them.

SAT® is a trademark registered by the College Board, which is not affiliated with, and does not endorse, this site.

← All guides