Single subjects take singular verbs, and plural subjects take plural verbs. But sometimes, the distinction isn’t so obvious, as I’ve discussed before.
Here’s a passage from Einsohn’s Copyeditor’s Handbook that had me wondering about subject-verb agreement:
In my professional experience I have found that two readings of galleys and two of page proofs will catch 99 percent of the errors. Unfortunately, the remaining 1 percent are often the mistakes that cause not only embarrassment but trouble.
I thought, “The remaining 1 percent are the mistakes that cause embarrassment? Doesn’t “1 percent” require a singular verb?”
I thought about how I would edit the sentence:
Unfortunately, the remaining 1 percent is sure to include the mistakes that cause not only embarrassment but trouble.
What does Einsohn herself have to say about this construction? In her list of 25 common “perplexities and controversies in subject-verb agreement,” percentages is number 20:
After the construction “x percent of y,” the verb is singular if y is a singular noun or a collective noun, and the verb is plural if y is a plural noun.
In this case, y is errors, which is plural, so Einsohn’s original sentence above is correct: “the remaining 1 percent are often the mistakes … ”
Above, I introduced another perplexity in subject-verb agreement:
percentages is number 20
Einsohn lists this case as a “collective idea,” which always requires a singular verb. Another example is “Fifty thousand words is a lot for a blog post.”
(No worries about that around here.)