Coordination and parallelism
Coordination joins units of equal status, and parallelism requires those units to have matching grammatical shape.
01 · Concept foundation
Understand the terms before applying the rule
Each term below names a different grammatical object. Open examples and compare their function rather than memorising a Vietnamese translation alone.
coordination/kəʊˌɔːdɪˈneɪʃən/
đẳng lậpThe linking of words, phrases or clauses of equal grammatical rank.
measure and compare; accurate but expensive
đo và so sánh; chính xác nhưng đắt
parallelism/ˈpærəlelɪzəm/
cấu trúc song songThe use of matching grammatical forms for coordinated or compared ideas.
to collect, to process and to report
thu thập, xử lý và báo cáo
correlative conjunction/kəˈrelətɪv kənˈdʒʌŋkʃən/
liên từ tương liênA paired conjunction whose two parts introduce parallel units.
both ... and; either ... or; not only ... but also
cả ... và; hoặc ... hoặc; không chỉ ... mà còn
Complete lesson scope
Do not stop at one formula
Coordination of words, phrases, clauses and sentences
Parallel forms after and, or, but and correlative pairs
Shared auxiliaries, ellipsis and gapping
Punctuation in compound sentences and lists
Decision boundary: Items joined at the same level should have comparable grammatical form and semantic function.
02 · Controlling rule
Coordination joins equivalent words, phrases or clauses. Parallelism requires comparable grammatical form and semantic function, correlative conjunctions must frame matching units, and independent clauses need a coordinator with appropriate punctuation or another valid sentence boundary.
X and/or/but X | both X and Y | not only X but also Y | clause, coordinator clauseCoordination and parallelism
Join words, phrases and clauses at the same grammatical level, maintain parallel form across coordinated ideas, and punctuate lists and compound sentences clearly.
Coordinate equivalent units
Coordination links units of equal grammatical rank. The coordinator does not automatically make unlike structures equivalent.
word + word | phrase + phrase | clause + clauseAnd adds, but contrasts, and or presents alternatives; yet and so also coordinate independent clauses.
Coordinate at one level at a time: noun with noun, phrase with phrase, clause with clause.
Shared material may be omitted only when the remaining structure is unambiguous.
The study measured water level, salinity and current velocity.
The grid was coarse, but the simulation remained stable.
Coordination by structural level
Identify the full span of each coordinated unit before judging parallelism.
| Level | Example | Parallel units |
|---|---|---|
| Word | stable but costly | adjective + adjective |
| Phrase | in the estuary and near the coast | prepositional phrase + prepositional phrase |
| Non-finite clause | to measure and to compare | to-infinitive + to-infinitive |
| Finite clause | The tide rose, but the gate remained closed. | independent clause + independent clause |
Correlative-pair control
Place the pair directly before structurally matching units.
| Pair | Meaning | Controlled example |
|---|---|---|
| both...and | addition of two | both accurate and efficient |
| either...or | choice | either reduce the step or refine the grid |
| neither...nor | negative of two | neither the data nor the method is adequate |
| not only...but also | addition with emphasis | not only reduced bias but also improved stability |
High-risk contrasts
After aimed to, both coordinated verbs should use the base form under the shared to.
Both must introduce two parallel verb phrases.
Not only pairs with but also, and the two verb phrases must be parallel.
Two independent clauses need a coordinator, semicolon or full stop, not a comma alone.
Concept and form check
Apply the system in context
Revise one IELTS-style paragraph containing a list and a compound sentence. Make every list parallel and explain each comma or coordinator choice.
- ✓Identify the full grammatical span of every coordinated unit.
- ✓Match form and semantic function across the series.
- ✓Use punctuation that reflects list and independent-clause boundaries.
03 · Worked examples
Observe form, function and meaning together
The study measured water level, salinity and current velocity.
Nghiên cứu đo mực nước, độ mặn và vận tốc dòng chảy.
The project aims to measure change, identify causes and evaluate risk.
Dự án nhằm đo biến đổi, xác định nguyên nhân và đánh giá rủi ro.
The method is both transparent and reproducible.
Phương pháp vừa minh bạch vừa có thể tái lập.
The grid was coarse, but the simulation remained stable.
Lưới thô, nhưng mô phỏng vẫn ổn định.
The northern station recorded a rise, and the southern station a decline.
Trạm phía bắc ghi nhận mức tăng, còn trạm phía nam ghi nhận mức giảm.
04 · High-risk contrast
Explain why one form fails, not only which answer is correct
The study aimed to measure salinity and improving forecasts.
The study aimed to measure salinity and improve forecasts.
The shared to governs two coordinated base verbs. Mixing to-infinitive structure with an -ing form breaks parallelism.
05 · Mastery check
Apply the rule before marking the lesson complete
Which sentence is grammatically acceptable in the target system?
Which description best defines “coordination”?
Which example is one of the verified target patterns in this lesson?
Which structural formula belongs to this lesson?
Complete all four checks, then submit a sentence for target-form feedback.
06 · IELTS Academic
Transfer grammar into a real communicative task
Parallel lists and controlled compound sentences make Task 1 processes, Task 2 arguments and Speaking comparisons easier to follow without artificial complexity.
Coordinate only units of equivalent grammatical rank.
Maintain parallel verb, noun, phrase or clause form across a series.
Place both/either/neither/not only at the actual divergence point.
Use punctuation that distinguishes lists from independent-clause coordination.