Correcting Errors in Subject-Verb Agreement

Sentence analysis

Richard Nordquist 

Here we will practice applying one of the most basic and yet also most troublesome rules of grammar: in the present tense, a verb must agree in number with its subject. Put simply, this means that we have to remember to add an -s to the verb if its subject is singular and not to add an -s if the subject is plural. It's really not a hard principle to follow as long as we can identify the subject and verb in a sentence. Let's have a look at how this basic rule works.

Compare the verbs (in bold) in the two sentences below:

Merdine sings the blues at the Rainbow Lounge.

My sisters sing the blues at the Rainbow Lounge.

Both verbs describe a present or ongoing action (in other words, they are in the present tense), but the first verb ends in -s and the second one doesn't. Can you give a reason for this difference?

That's right. In the first sentence, we need to add an -s to the verb (sings) because the subject (Merdine) is singular. We omit the final -s from the verb (sing) in the second sentence because there the subject (sisters) is plural. Remember, though, that this rule applies only to verbs in the present tense.

As you can see, the trick to following the basic principle of subject-verb agreement is being able to recognize subjects and verbs in sentences. If that's giving you a problem, try reviewing our page on the Basic Parts of Speech.

Here are four tips to help you apply the principle that a verb must agree in number with its subject:

TIP #1

Add an -s to the verb if the subject is a singular noun: a word that names one person, place, or thing.

Mr. Eko drives a hard bargain.

Talent develops in quiet places.

TIP #2

Add an -s to the verb if the subject is any one of the third-person singular pronouns: he, she, it, this, that.

He drives a minivan.

She follows a different drummer.

It looks like rain.

This confuses me.

That takes the cake.

TIP #3

Do not add an -s to the verb if the subject is the pronoun I, you, we, or they.

I make my own rules.

You drive a hard bargain.

We take pride in our work.

They sing out of key.

TIP #4

Do not add an -s to the verb if two subjects are joined by and.

Jack and Sawyer often argue with each other.

Charlie and Hurley enjoy music.

So, is it really that simple to make subjects and verbs agree? Well, not always. For one thing, our speech habits sometimes interfere with our ability to apply the principle of agreement. If we have a habit of dropping the final -s from words when we talk, we need to be particularly careful not to leave off the -s when we write.

Also, we have to keep a certain spelling rule in mind when adding -s to a verb that ends in the letter -y: in most cases, we need to change the y to ie before adding the s. For example, the verb carry becomes carries, try becomes tries, and hurry becomes hurries. Are there exceptions? Of course. If the letter before the final -y is a vowel (that is, the letters a, e, i, o, or u), we simply keep the y and add -s. So say becomes says, and enjoy becomes enjoys.

Finally, as we see in our page on Tricky Cases of Subject-Verb Agreement, we have to be particularly careful when the subject is an indefinite pronoun or when words come between the subject and verb.