Parallel Structure: The Grammar Trick That Makes TOEFL Writing Sound Clean

You are wrapping up an Academic Discussion response. The position is clear, the example is concrete, and you want to end strong. You type: "Universities should focus on teaching critical thinking, helping students collaborate, and to prepare them for the workforce." You hit submit. A rater reads the sentence and feels the tiny bump — two -ing phrases and then a to-infinitive, all in the same list. The idea is fine. The rhythm just broke. Welcome to parallel structure, the smallest grammar topic that produces the biggest swing in perceived polish.

Parallelism is what makes a sentence feel professional. When elements in a list or comparison share the same grammatical form, the reader's ear locks into the pattern and absorbs the meaning quickly. When one element breaks the pattern, the reader stumbles — often without consciously knowing why. Under time pressure on TOEFL iBT 2026, parallel structure is one of the first things to slip and one of the easiest things to repair.

Why This Matters on TOEFL iBT 2026

The TOEFL Writing rubric specifically rewards "syntactic variety and appropriate word choice." Parallel structure is half of that signal. Lists, comparisons, and correlative pairs are everywhere in academic writing, and a clean parallel layer is the visible marker of a careful writer.

In Reading, parallel structure is a comprehension aid. Academic passages often present three or four examples in a single sentence — and the parallel form is the cue that they belong together. Spotting the pattern speeds up your reading.

In Speaking — especially Take an Interview — a parallel triplet ("I want to study abroad to learn the language, to experience the culture, and to build international contacts") sounds confident and organized in under twelve seconds. Raters notice.

In Writing, parallelism does its biggest work in the What's the Right Way to Write an Email on the TOEFL 2026? task, where polite phrasing often comes in pairs and triplets, and in Academic Discussion responses, where listing reasons or examples is a default move.

The Trap

Parallel structure breaks in three predictable places under time pressure.

Items in a list. When you give two or three examples, they should share grammatical form. Three -ing phrases, three to-infinitives, three noun phrases. The error is mixing forms: "reading, swimming, and to hike." The first two are -ing gerunds; the third is an infinitive. Fix it to "reading, swimming, and hiking" or "to read, to swim, and to hike." Either is fine — what matters is consistency.

Correlative conjunctions. English has several pair-words that must connect parallel structures: either…or, neither…nor, not only…but also, both…and, whether…or, not…but. Whatever comes after the first word in the pair must match whatever comes after the second. "She is not only intelligent but also works hard" breaks parallelism: intelligent is an adjective, works hard is a verb phrase. Fix it to "She is not only intelligent but also hardworking" or "She not only is intelligent but also works hard."

Comparisons. When you compare two things, the grammatical form on both sides of the comparison must match. "Writing essays is harder than to give speeches" mixes a gerund and an infinitive. Fix it to "Writing essays is harder than giving speeches." Same idea with as…as comparisons: "Reading is as useful as to listen" should be "Reading is as useful as listening."

There are also three sub-traps worth naming.

Verb tense parallelism. "She studied for the test, attended every class, and is doing extra problems" mixes past simple with present continuous. Pick one tense and hold it across the list.

Article and preposition parallelism. If the first item in a list includes a preposition or article, the others should too — or none should. "She works in the lab, library, and the office" leaks because the appears with office but not lab or library. Either repeat the article each time or use it once: "She works in the lab, the library, and the office" or "She works in the lab, library, and office."

Subject-verb parallelism in long sentences. Long sentences with multiple verbs sometimes shift voice or subject mid-stream. "The committee approved the budget, the schedule was reviewed, and the chair announced the next meeting" mixes active and passive constructions. Aligning the voice — all active or all passive — makes the sentence feel coherent.

Wrong / Better / Why

Where It Shows Up

Academic Discussion responses. Most strong responses use at least one triplet — three reasons, three examples, or three benefits. Each triplet is a parallelism test. Breaking parallel structure in the closing sentence is a frequent leak: "We should focus on access, affordability, and improving quality" mixes two noun phrases with one verb phrase.

Write for an Academic Discussion. Connecting two or three academic points in a row almost always requires parallel structure: "The professor challenges the first claim by noting X, citing Y, and arguing Z." Keeping the three -ing verbs parallel is the difference between a clean response and a choppy one.

Write an Email. Polite phrasing relies on parallel pairs: "I would like to confirm the date and to ask about the agenda" or "I would like to confirm the date and ask about the agenda" — pick one pattern and hold it. Mixed forms in a polite email read as careless.

Take an Interview. A parallel triplet is a high-yield speaking move: "I want to take the course because it builds analytical skills, because it covers real cases, and because the professor is excellent." The repetition reinforces clarity in a short answer.

Fast Fix

Whenever you see a list, a comparison, or a correlative pair in your writing, run a three-step check.

First, identify the connector or comparison word: and, or, but, as…as, more than, both…and, either…or, not only…but also. These words almost always introduce parallel pairs or lists.

Second, read the grammatical form of each item connected by that word. Is item one a gerund? Item two should be a gerund. Is item one a noun phrase starting with the? Item two should be the same — or the the should be dropped from both.

Third, rewrite the breaking item to match. Almost every parallelism fix is a one-word change: replace to hike with hiking, replace works hard with hardworking, replace being creative with creativity.

A bonus heuristic: when in doubt, rewrite the list as a vertical bullet list in your head:

• reading
• swimming
• to hike

If one bullet looks different from the others, fix it. This trick takes three seconds and catches almost every parallel break.

Mini Practice

1. Make the list parallel: She enjoys reading novels, watching films, and to listen to podcasts.
2. Fix the correlative pair: He is not only a strong writer but also speaks well in public.
3. Repair the comparison: Studying with classmates is more effective than to study alone.
4. Align the verbs: The professor reviewed the syllabus, the assignments were explained, and answered our questions.
5. Make the prepositions consistent: Students were instructed to bring a notebook, pen, and their textbook.

Possible improved versions: (1) She enjoys reading novels, watching films, and listening to podcasts. (2) He is not only a strong writer but also a strong public speaker. (3) Studying with classmates is more effective than studying alone. (4) The professor reviewed the syllabus, explained the assignments, and answered our questions. (5) Students were instructed to bring a notebook, a pen, and a textbook.

What to Check Before You Submit

Spend thirty seconds on a parallel-structure pass before you click submit. Search your response for the words and, or, but, both, either, neither, not only, as, and than. Each of these flags a place where two or more elements should match. For every match you find, ask whether the two sides share the same grammatical form. If they don't, change the smaller side to match the larger side — usually a one-word fix. Then read your longest sentence out loud in your head and listen for the rhythm. If you stumble on the final item in a list, the list probably broke parallelism. A clean parallel layer is the quietest, most reliable upgrade you can give a TOEFL response.