Understanding Subject-Verb Agreement

 Importance: ★★★

Discussion

Compared to many other languages, English does not often require a verb to agree with the subject in person and number. However, there is one important exception: In every sentence in the present tense (and in a few cases in the past tense—see below), the verb always takes a final -s ending if the subject is third person and singular.

What does that mean? Essentially, any subject will fall into one of six categories, depending on whether it is singular or plural, and first-, second-, or third-person:

The only one of these six categories that requires any special ending on the verb is the third-person singular. That sounds easy enough. However, consider this: This category includes far more possible subjects than most of the others. First-person singular essentially means "Any sentence in which the subject is I." Similarly, in first-person plural, the subject is (almost) always we. In modern English, second-person pretty much always means that the subject is you.

All other subjects are third-person, either singular or plural. In stark contrast to the first person and second person, there is an infinite number of possible third-person subjects: Jorge's parents, the escaped chinchilla, that peanut butter you got on your pants, the opposite of the notion of free will, and so on forever.

So, here is one approach to dealing with subject-verb agreement in English: Any time a setence has the subject I, you, or we, you know that you don't need to add anything to the verb. In all other cases, whether you need to do so depends on whether the subject is singular or plural.

Here is a mnemonic device (memory-aid) that may help you: "Only one -s at a time". Most plural subjects in English end in -s; these are the ones that do not need an -s on the verb. By contrast, most singular subjects do not end in -s; these are the ones that do require an -s on the verb. So, most of the time, you will have only one -s at a time. (Obviously, this is not foolproof: There are singular subjects like "grass" and plural subjects like "people", but for the most part, the rule holds.)

Of course, in real life, it can be difficult to make sure a verb agrees with its subject. Let's look at some examples from student writing.

Many e-readers are equipped with screens that uses a technology called e-paper; these special screens are made to mimic the page of a printed book.

Here, the subject of use is screens. Because this is a plural subject, the verb should be uses:

Many e-readers are equipped with screens that use a technology called e-paper; these special screens are made to mimic the page of a printed book.

Of course, in this case a singular subject would work as well, and then uses would be correct:

Many e-readers are equipped with a screen that uses a technology called e-paper; these special screens are made to mimic the page of a printed book.

Note that the verb "to be" is irregular; the third-person singular form is is, which conveniently ends in an -s anyway. Here, is is incorrectly used with a plural subject:

This conflict is about identity, and it clearly shows how society’s values is trying to shape the protagonist into becoming something that she does not want to become.

This conflict is about identity, and it clearly shows how society’s values are trying to shape the protagonist into becoming something that she does not want to become.

Summary

A present-tense verb takes an -s if the subject is third-person and singular.

Further Discussion

One of the most common reasons for agreement errors is the presence of a "decoy" noun that looks like the subject but is not:

The frequency of the two meanings differ between registers.

The frequency of the two meanings differs between registers.

Here, if we just look at meanings differ, it looks correct, with only one -s. However, the subject here is actually the frequency of the two meanings. The head of this noun phrase is frequency, and it is the head of the noun phrase that a verb must agree with. In a sense, it's the frequency differs.

So remember: You need to figure out what noun is actually the head of the subject, because that's the one the verb agrees with.

Here are some more examples:

The focus of all three texts are homelessness in the USA.

The focus of all three texts is homelessness in the USA.

The biggest misconception on the part of those who do not approve of hen seem to be that hen is supposed to replace the words han and hon, which is not true.

The biggest misconception on the part of those who do not approve of hen seems to be that hen is supposed to replace the words han and hon, which is not true.

Note that, in this last example, the verb seem has a very long subject indeed: The biggest misconception on the part of those who do not approve of hen. What is the head of this noun phrase? It's misconception, which is singular—hence the need for the form seems. It would very easy to let one of the three noun phrases within that noun phrase (part, those, hen) act as a "decoy", but none of these actually have any relationship with the word seem—in fact, those is the subject of another verb, approve, which is part of the post-modification of misconception. Do you see now why we teach you grammar?

For more discussion of the complexities of subject-verb agreement, see Working with Subject-Verb Agreement.

Related Topics

Working with Subject-Verb Agreement