Be the hit of your holiday party! Amaze your friends! Impress your family! Be one of those people who uses the correct verb in the phrasing of “one of those”!

Of course, unless one of those people are really steeped in English, not many are likely to notice that in both of those “one of those” phrases, the verb was wrong. For now, at least.

Many people learned that prepositional phrases—many of which start with “of”—drop out of the equation when deciding on how to make the verb agree with its subject. So if you wrote “The box of cookies on the counter (is or are) mine,” you were told that the subject was “box,” so you wanted the singular verb “is”—the plural in “of cookies” didn’t count.

That’s pretty straightforward. But when you replace “box” with “one,” the phrasing becomes one of those things that always (confuses or confuse?) us.

To figure out whether the verb should be singular or plural, some people will think “of those things” is prepositional, and will do what their English teachers said to do: Say “One … confuses us.” They’d make “one” the subject, and so the verb would be singular.

And they’d be wrong.

Perhaps with a better English teacher, you would have turned the sentence around and said: “Of those things that confuse us, that is one.” You’d recognize that in the phrase “one of those things that,” “things” is the subject, not “one.”

But both of those require work. There’s an even easier way, though. As Patricia T. O’Conner points out so succinctly in Woe Is I: “If a that or a who comes before the verb, it’s plural: He’s one of the authors who say it best. If not, it’s singular: One of the authors says it best.”

One of the problems with having the right answer when nearly everyone else is wrong is that pretty soon, you’ll be the one of those who (is or are) wrong. Garner’s Modern American Usage says that the construction “one of the few that is,” which, as we see from O’Conner’s test, should be are, is at Stage 4 on the Language-Change Index. That means using a singular verb when, grammatically speaking, a plural one is required in a “one of the” phrase is acceptable to all but “a few linguistic stalwarts.”

Our suggestion: Be one of those stalwarts who get it right. And now, you can explain it to (more than one of) those who don’t get it.

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Merrill Perlman managed copy desks across the newsroom at The New York Times, where she worked for 25 years. Follow her on Twitter at @meperl.