This is a guest post by Jacquelyn Landis. If you want to write for Daily Writing Tips check the guidelines here.
My copyediting students occasionally stumble when they see a sentence like this one:
All the shirt needs is/are buttons.
Which is it? The singular is or the plural are? Most of us know instinctively that the verb form must match the subject form in number. This is called subject-verb agreement. But sentences such as this one seem ambiguous since all can be either singular or plural when it’s used as an indefinite pronoun.
It would be an easy choice if all were followed by a prepositional phrase to help us determine whether it’s singular or plural:
All of the water is draining. (singular)
All of us are tired. (plural)
So, what many writers would do with the problematic sentence is turn to buttons to help them make the decision. And since buttons is plural, then the verb should be plural, too. Right? Well, not quite.
Buttons in this sentence is what’s called a predicate nominative. Now, I know grammar terms like this are enough to send most people screaming into the night, but stick with me. A predicate nominative is simply a noun that is the same as the subject. It describes it further, just as buttons describes all.
Predicate nominatives do not determine the verb form; only the subject can do that. And the subject of our puzzling sentence, all, is a singular pronoun even though what it substitutes for (buttons) is plural. It stands on its own with no help from a prepositional phrase. When this is the case, it’s singular.
Thus, the correct verb form is also singular, so this is how our sentence should read:
All the shirt needs is buttons.
Follow the same logic when the subject is what:
What he ordered was steamed clams.
Whenever I’m tempted to use a plural verb in sentences such as this, I remind myself of a song: “All I Want for Christmas Is My Two Front Teeth.” The song’s authors were teachers, and they got it right.
Jacquelyn teaches an online copyediting course to students from around the world Education to Go. Check it out.