Sentence Structure Advanced

Parallel Structure

Master parallel structure (parallelism) in English writing. Learn how to keep lists, pairs and comparisons grammatically consistent for cleaner, more professional PTE and IELTS writing.

What is Parallel Structure?

Parallel structure (parallelism) means using the same grammatical form for items in a series, list, or comparison. Parallel structure creates clarity and rhythm in writing, and its absence — broken parallelism — is a common writing error that lowers IELTS Writing band scores and PTE Grammar scores.

Rules & Formation

Items in a list must use the same grammatical form: all nouns, all infinitives, all gerunds, or all clauses.
Items joined by coordinating conjunctions (and, but, or, nor, yet) must be parallel.
Correlative conjunctions (both...and, either...or, neither...nor, not only...but also) require parallel elements on both sides.
Comparisons with "than" or "as...as" require parallel elements.
After the first instance, articles (the, a, an) and prepositions can be omitted from subsequent parallel items if they match.

Examples

❌ She enjoys reading, to write, and swim. → ✅ She enjoys reading, writing, and swimming.

❌ The policy aims to reduce costs, improving efficiency, and the expansion of services. → ✅ The policy aims to reduce costs, improve efficiency, and expand services.

✅ Not only is the programme affordable, but it is also effective.

✅ The government must either increase funding or reduce expenditure.

✅ Learning a language requires time, patience, and consistency.

❌ The report is more detailed than last year's was written. → ✅ The report is more detailed than last year's.

🎯 Exam Tip — PTE & IELTS

Parallel structure is a reliable way to improve IELTS Writing Task 2 Coherence & Cohesion and Grammatical Range scores simultaneously. Use it deliberately in thesis statements: "This essay will examine the causes, analyse the effects, and propose several solutions." Also use it in topic sentences for body paragraphs. Broken parallelism is immediately noticeable to examiners and AI scoring engines.

Frequently Asked Questions

What is the most common parallel structure error in academic writing?

Mixing infinitives and gerunds in a list: "The programme aims to educate, training, and employing workers." The correct parallel form: "The programme aims to educate, train, and employ workers." (all infinitives) or "The programme focuses on educating, training, and employing workers." (all gerunds). Choose one form and apply it consistently across the list.

How can I use "not only...but also" for parallel structure in IELTS?

"Not only...but also" must connect the same grammatical elements. "Not only is the policy expensive [adjective phrase], but it is also ineffective [adjective phrase]." "Technology not only improves [verb] efficiency but also reduces [verb] costs." Using this correlative conjunction correctly demonstrates sophisticated grammar and directly contributes to your IELTS Grammatical Range & Accuracy score.

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