Grammar / usage: Parallel structure
Subtopic: Section D · Grammar
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Rule: when two or more items are joined by a coordinating conjunction ('and', 'or', 'but'), correlative conjunction ('either … or', 'not only … but also'), or by comparison ('rather than', 'as much as'), they must share the same grammatical form — all noun phrases, all verb phrases, all gerunds, all infinitives.
Approach: identify the conjunction; check the items on either side; force them into the same grammatical form. The repair is usually quick — change a gerund to an infinitive, or rephrase a noun phrase to match.
What an examiner expects: rule stated cleanly; corrected sentences with the parallel items underlined; a one-line justification.
Common pitfalls: (1) mixing gerunds and infinitives ('She likes hiking and to swim'); (2) breaking parallelism in lists of three or more; (3) breaking parallelism across correlative pairs ('not only … but also').
- Rule: items joined by conjunctions must share grammatical form.
- Lists of nouns: all nouns.
- Lists of verbs: all in the same form (all -ing, all infinitive, all simple).
- Correlative pairs: 'either … or', 'neither … nor', 'not only … but also', 'both … and' — items after each member must be the same form.
- Comparison: 'rather than X, Y' — X and Y must be the same form.
- Headings and bullet points also follow parallelism rules.
- Repair: change one item to match the others, not the other way around in isolation.
- Watch articles: 'a book, a pen and the eraser' — drop or repeat articles consistently.
- Watch prepositions: 'interested in art, music and in literature' — repeat or drop consistently.
- Practice sentences below.