Which sentence correctly uses a dash to interrupt a compound subject?

Which sentence correctly uses a dash to interrupt a compound subject?

• A. Tom and Jerry - the duo known for mischief - arrived.
• B. Tom and Jerry - the duo known for mischief arrived.
• C. Tom and Jerry, the duo known for mischief arrived.
• D. Tom - and Jerry - arrived.

Answer: (A)

Dashes can interrupt a compound subject when a nonessential description is inserted to modify both parts of the subject. In the correct sentence, "Tom and Jerry" is the compound subject, and the phrase "the duo known for mischief" adds extra information about them without changing who arrived. The dashes set off that nonessential descriptor on both sides, so the subject remains plural and the verb arrived correctly agrees with it. You could remove the interrupting phrase and the sentence still makes sense: "Tom and Jerry arrived." The other forms misuse punctuation. One leaves the interruption without a matching closing dash, so the boundary of the parenthetical is incomplete. Another uses a comma instead of proper dash delimitation, and the appositive isn’t properly enclosed. The last option places dashes inside the subject itself, breaking the compound subject rather than inserting additional information about it.

Dashes can interrupt a compound subject when a nonessential description is inserted to modify both parts of the subject. In the correct sentence, "Tom and Jerry" is the compound subject, and the phrase "the duo known for mischief" adds extra information about them without changing who arrived. The dashes set off that nonessential descriptor on both sides, so the subject remains plural and the verb arrived correctly agrees with it. You could remove the interrupting phrase and the sentence still makes sense: "Tom and Jerry arrived."

The other forms misuse punctuation. One leaves the interruption without a matching closing dash, so the boundary of the parenthetical is incomplete. Another uses a comma instead of proper dash delimitation, and the appositive isn’t properly enclosed. The last option places dashes inside the subject itself, breaking the compound subject rather than inserting additional information about it.