Punctuation
Parentheses and brackets
If removing the parenthetical leaves a complete sentence, the punctuation is probably right.
Why this happens
Parentheses tuck in optional detail; brackets add editorial notes inside quotations or clarify material. Problems include leaving parentheses unclosed, overstuffing main sentences with asides, or changing quoted words inside brackets without signalling the edit. Material inside should be skippable without breaking the grammar of the host sentence.
See it in a sentence
IncorrectThe results (which were unexpected showed a clear trend.
CorrectThe results (which were unexpected) showed a clear trend.
Teaching note: Close parentheses — the aside must not swallow the main verb.
IncorrectShe wrote that the policy was unfair and discriminatory [sic].
CorrectShe wrote that the policy was "unfair and discriminatory" [sic].
Teaching note: Quotations often need marks; [sic] shows quoted error preserved.
IncorrectContact the team (email: team@example.com for details.
CorrectContact the team (team@example.com) for details.
Teaching note: Parenthetical contact info must be fully enclosed.
More examples
Punctuation: place a period outside if the parenthetical is not a full sentence.
The trial ended early (see Appendix B).
Square brackets add clarification: He [the manager] approved it.
Brackets show your insertion, not the original author's words.
Nested parentheses are awkward — rephrase or use dashes instead.
Avoid (group A (subset B) results).
Citation brackets [1] differ from editorial brackets — follow your style system.
Academic formats vary on bracket use for references.
Quick check
The average score (n = 45 increased sharply in round two.
Show the fix
The average score (n = 45) increased sharply in round two. Close the parenthesis before increased so the main clause stays intact.
Practice this topic in Wrytesmart
Open the grammar workspace to complete interactive exercises for parentheses and brackets. You will spot errors, fill blanks, and transform sentences — always with teaching notes that explain the principle, not just the correction.
Master parentheses and brackets in context
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