SAT® · Reading and Writing: Form, Structure, and Sense — Agreement
A Nonrestrictive Clause Between Subject and Verb
When a clause or phrase is parked between the subject and the verb, delete it mentally. The verb must agree with the subject outside that clause, not with any noun hiding inside it.
The test loves to put real distance between a subject and its verb, because distance makes you forget what the subject actually was. If the subject is singular but a plural noun shows up right before the verb, your ear starts voting for the wrong word. The fix is mechanical, not intuitive: find the subject, find the verb, and ignore everything sitting between them that is boxed off by punctuation.
That boxed-off material is a nonrestrictive clause or phrase: extra information the sentence doesn't need to make sense. It always arrives fenced off in pairs - two commas, two dashes, or a set of parentheses - and that pairing is the signal to delete. Cross out everything from the first mark to the second, push the subject and verb together, and read what's left. If it sounds right alone, the agreement is right. The fence works the same way whether it's built from commas, dashes, or parentheses; only the punctuation style changes, never the rule.
This sits right next to every other agreement trap built on distraction: prepositional phrases, appositives, and parenthetical asides all work the same way. Once you can delete an interrupter automatically, you're ready for trickier cases where the interrupter itself contains a subject-verb pair, or where two interrupters stack back to back. The core move stays identical: the noun inside the fence never gets a vote on the main verb outside it.
Key terms
- Nonrestrictive clause
- A clause giving extra, non-essential information, set off by punctuation on both sides.
- Interrupter
- Any word group boxed off by paired commas, dashes, or parentheses between a subject and its verb.
- Subject-verb agreement
- The rule that a verb's form must match whether its subject is singular or plural.
- Appositive
- A noun phrase that renames or describes another noun right next to it, often set off by commas.
Watch it explained
- How it worksHow do the paired commas mark off exactly what to delete before you check the main verb?
- Going furtherWhat changes when the interrupter arrives as a pair of dashes or parentheses instead of commas?
- Worked exampleWalk me through fixing 'The telescope, which cost billions and took decades, were launched in 2021'.
- Common mistakeWhy doesn't the plural noun trapped inside an interrupter get a vote on the main verb?
Check yourself
End of topic.