Use dashes or parentheses to set off parenthetical information when appropriate.
Use matching dashes or parentheses to set off extra parenthetical information.
Core Idea
Dashes and parentheses set off extra information that interrupts a sentence. The critical rule: they must come in pairs when the interruption falls in the middle of a sentence. Open with a dash, close with a dash. Open with a parenthesis, close with a parenthesis.
Understanding
Dashes (—) and parentheses work like bookends around parenthetical information—material that adds detail but isn't grammatically necessary.
Dashes give the interruption emphasis:
→ "The experiment—the first of its kind—produced unexpected results."
Parentheses downplay the interruption:
→ "The experiment (the first of its kind) produced unexpected results."
Both are correct. The SAT doesn't test your preference—it tests consistency.
The pairing rule is what the SAT actually tests. If an interruption starts with a dash, it must end with a dash (unless the interruption finishes the sentence, where a period takes over). You can't open with a dash and close with a comma, or open with a parenthesis and close with a dash.
To check: mentally remove everything between the pair of dashes or parentheses. The remaining sentence should be grammatically complete.
→ "The experiment produced unexpected results." ✓
Step by Step
- Identify the parenthetical information—the extra material that could be removed.
- Check whether it falls mid-sentence (needs a closing mark) or at the end (period closes it).
- If mid-sentence, ensure the same mark opens and closes: dash with dash, or parenthesis with parenthesis.
- Remove the parenthetical and read what remains. Does it form a complete, grammatical sentence?
- Eliminate any answer choice that mixes marks (e.g., dash to open, comma to close).
Misconceptions
- "You can close a dash with a comma." No. If a dash opens the interruption, a dash must close it (or the sentence must end). A comma is not a substitute closing mark.
- "Parentheses and dashes are always interchangeable." Grammatically, often yes. But on the SAT, if one end of the pair is already set (e.g., a dash appears before the interruption), the answer must match with the same mark.
- "Dashes are informal and shouldn't appear on the SAT." Em dashes are standard in formal writing and appear regularly in SAT passages.
Worked Example
The okapi—a reclusive mammal native to the dense rainforests of the Democratic Republic of the ______ more closely related to the giraffe than to any species of horse or zebra.
Which choice completes the text so that it conforms to the conventions of Standard English?
Select an answer to see the explanation