Grammar rule cards › Boundaries (sentence structure and punctuation)
Nonessential information: matching punctuation
The rule
Extra information that could be removed without changing the main meaning is set off by a matching pair of commas, dashes or parentheses. Do not mix them.
✔ Correct: The bridge—completed in 1932—is now a landmark.
✘ Incorrect: The bridge—completed in 1932, is now a landmark.
→ Fix: Use two dashes or two commas, not one of each.
Tip: Delete the middle part. If the sentence still works, it needs matching punctuation on both sides.
Practice: 10 questions
Which choice completes the text so that it conforms to the conventions of Standard English?
Original explanations and questions written for AUSLEX, not official College Board material. SAT is a trademark of College Board.