Language Arts In this subject-verb agreement article we learn the rules of when to use a singular verb and when to use a plural form of the verb. Read more to learn some of the basic rules and tricks to help you understand subject-verb agreement.

The basic tenet of subject-verb agreement is that singular subjects take singular verbs and plural subjects, as well as the first person singular (I) and second person singular (you used as a singular) take plural verbs. To put it another way: the singular verb is only used with the third person singular. The plural verb is used for everything else.

The plural verb is the same as the base form (also called the “uninflected form”) of the verb. This article discusses some of the most important points that will help you avoid errors in this area.

The Role of S

The first thing that can be tricky about subject-verb agreement is that while regular plural nouns in English are formed with -s, it is the singular verb form that (in most cases) features an -s ending. So the proper match is not a match of forms, but of meanings:

Singular: The ant goeS marching.

Plural: The antS go marching.

Of course, there are also irregular nouns that do not end in -s,

Singular: The mouse squeakS.

Plural: The mice squeak.

and the singular of some nouns ends in -s,

Singular: The grasS growS.

Plural: The grasseS grow.

so you can't use the s as a rule, but only as a guide in most cases.

Be Has More Than Two Forms

Most English verbs, like go, squeak, and grow have only a singular and plural form. The verb to be, on the other hand, has a special form for first person singular in addition to singular and plural:

Singular: The zebra is running.

Plural: The zebras are running.

First Person Singular: I am running.

Nouns With One Form

When the singular and plural form of a noun are identical, you will need to rely on context, not form to determine if the noun is singular or plural. If there is no definitive context, it is impossible to say which verb form is correct:

Compare these sets of sentences. In the first, there is nothing in the context to guide the choice of verb.

The sheep is in the meadow.
The sheep are in the meadow.

In these sentences, however, there are clues to let you know which verb form to use:

My sheep Clive is in the meadow.
The sheep are in the meadow, but the cows are in the corn.

Auxiliary Verbs

The modal verbs have only one form, so subject-verb agreement does not apply to them:

May:
Fish may swim.
Birds may fly.
I may drive.

Could:
The leopard could leap.
I could bake cookies.
The goldfish could be responsible.

In cases in which no modal verb is involved, only the first verb in the verb phrase, whether it is a main verb or an auxiliary verb, must agree with the subject. Here are examples:

Auxiliary Be:
I am tired.
James is tired.
The pigeons are tired.

Auxiliary Have:
I have swum.
Owen has swum.
The seals have swum.

Main Verb:

Who's ready for ice cream?
I am.
Sally is.
Randall and Algy are.
Jeremy has to tie his shoe first.
The twins have to put their towels away.
Polly wants chocolate.
Yoko and Francie want butter pecan.

Two or More Subjects

When there are multiple subjects, one key element to check in order to decide whether to use a singular or plural verb is the conjunction that connects them.

Singular subjects connected by or or nor take a singular verb:

Either Simon or Fred is at home.
Neither Simon nor Fred is in the kitchen.

Singular subjects connected by and take a plural verb:

Both Simon and Fred are in the basement playing table tennis.

If the two subjects would independently take different verb forms, it's most common to use the plural form with or or nor.

Either you or Simon are due to wash the dishes tonight. (You - >are; Simon - >is)