Dr. Richard Nordquist is professor emeritus of rhetoric and English at Georgia Southern University and the author of several university-level grammar and composition textbooks.
Updated on February 15, 2019Here you 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 you 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 you 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:
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, you need to add an -s to the verb (sings) because the subject (Merdine) is singular. You 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 basic parts of speech first.
Here are four tips to help you apply the principle that a verb must agree in number with its subject:
Add an -s to the verb if the subject is a singular noun: a word that names one person, place, or thing.
Add an -s to the verb if the subject is any one of the third-person singular pronouns: he, she, it, this, that.
Do not add an -s to the verb if the subject is the pronoun I, you, we, or they.
Do not add an -s to the verb if two subjects are joined by and.
So, is it really that simple to make subjects and verbs agree? Well, not always. For one thing, speech habits sometimes interfere with the ability to apply the principle of agreement. If you have a habit of dropping the final -s from words when you talk, you need to be particularly careful not to leave off the -s when you write.
Also, you have to keep a certain spelling rule in mind when adding -s to a verb that ends in the letter -y: in most cases, you 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), you simply keep the y and add -s. So say becomes says, and enjoy becomes enjoys.
Finally, as is the case with some trickier cases of subject-verb agreement, you have to be particularly careful when the subject is an indefinite pronoun or when words come between the subject and verb.