Parallel structure (also called parallelism) means that words, phrases, or clauses joined by conjunctions must have the same grammatical form. This is especially important with correlative conjunctions.
The Rule
Elements connected by either/or, neither/nor, both/and, not only/but also must be the same part of speech and grammatical structure.
Both / And
| Incorrect | Correct | | ------------------------------------------------- | -------------------------------------------------- | | She is both smart and has talent. | She is both smart and talented. | | He enjoys both swimming and to run. | He enjoys both swimming and running. | | The movie was both exciting and a thrill. | The movie was both exciting and thrilling. |
Either / Or
| Incorrect | Correct | | ---------------------------------------------------- | ------------------------------------------- | | You can either pay now or later you can pay. | You can pay either now or later. | | She will either call or she will email. | She will either call or email. | | He wants either to go home or stay here. | He wants to go either home or here. |
Neither / Nor
| Incorrect | Correct | | ---------------------------------------------------- | --------------------------------------------- | | She neither likes coffee nor tea. | She likes neither coffee nor tea. | | He neither called nor did he write. | He neither called nor wrote. | | The food was neither tasty nor it was fresh. | The food was neither tasty nor fresh. |
Not only / But also
| Incorrect | Correct | | ---------------------------------------------------------------- | ------------------------------------------------------------------- | | She is not only a singer but also dances. | She is not only a singer but also a dancer. | | He not only finished the project but also helped others. | He not only finished the project but also helped others. ✅ | | The car is not only fast but also it is economical. | The car is not only fast but also economical. |
Parallelism with Verbs
When the paired elements are verbs, keep the same tense and form.
- She not only won the race but also broke the record. (both past tense)
- He both speaks French and writes it fluently. (both present tense)
Parallelism with Prepositional Phrases
- The gift was for both you and me. (both objects of preposition)
- He traveled not only to Paris but also to Rome. (both to + city)
Parallelism with Clauses
- Either you can come with us, or you can stay home. (both full clauses)
- Neither did she call, nor did she write. (both inverted clauses)
Quick Test
Fix the faulty parallelism in these sentences:
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She is not only kind but also has intelligence. → She is not only kind but also intelligent.
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He wants either to travel or staying home. → He wants either to travel or to stay home.
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The company needs both more workers and to increase production. → The company needs both more workers and more production.