Subject-verb agreement

If a verb does not agree with its subject in number, you have the grammatical error called subject-verb disagreement. You want to correct the error so that you will have subject-verb agreement!

A verb must agree with its subject in number.

• If the subject is singular, the verb must be singular.
• If the subject is plural, the verb must be plural.

Singular subject

When there is a singular subject, you must use a singular verb.

Quite often, the difficulty is deciding which word is the subject, so that you can make the verb agree with it.

 Mary does her homework regularly.

This is a simple sentence. Ask the question Who does her homework regularly? and you get the answer Mary. Therefore, Mary is the subject of the sentence, and does is the verb. Because Mary is singular, the verb does must be singular, which it is.

Note: We add an s to a verb to make it singular, but we add an s to a noun to make it plural!

Occasionally, a singular subject will end with an s, but it is still singular. For example, SickKids is the partial name of a charitable foundation, SickKids Foundation. However, the foundation is more often referred to as SickKids. Therefore, it is singular, even though it looks plural.

Plural subject

When there is a plural subject, you must use a plural verb.

 The girls do their homework regularly.

Since there is more than one person doing homework regularly, the subject is plural, so the verb must be plural, which do is.

The pronoun "you"

The pronoun you always takes a plural verb, even though it may be referring to only one person.

 You are responsible for your actions.

Modifiers between subject and verb

Often there will be modifiers between the subject and the verb, so it is more difficult to determine the subject.

 The father of the children does not help them with their homework.

In the sentence above, is father or children the subject?

To determine the subject, you find the verb and ask who or what is doing the action. When you ask the question Who does not help them with their homework?, you get the answer father. Therefore, father is subject of the verb. Since the noun father is singular, a singular verb does is required.

You need to know that children cannot be the subject of the sentence because it is the object of the preposition of. The phrase of the children is a prepositional phrase, so any word in that phrase can never be the subject of the sentence.

 The current provisions of this law support domestic violence.

When you ask the question What supports domestic violence?, you could respond with provisions or law. One word is singular and the other is plural. However, only one of these is the actual subject of the sentence.

You recall that law cannot be the subject of the sentence because it is the object of the preposition of. The phrase of this law is a prepositional phrase, so any word in that phrase can never be the subject of the sentence.

Therefore, provisions is the subject of the sentence. Since provisions is plural, the verb must be plural, which support is.

Compound subject: singular

Sometimes, even though the subject appears compound, it is dealing with one person, thing, or idea. Therefore, the subject is singular.

 The secretary and treasurer was at the meeting.

In this case, one person is both secretary and treasurer, so the subject is singular and requires a singular verb.

Note the absence of the before treasurer in the sentence, an indication that there is only one person.

Compound subject: plural

A compound subject is two nouns or pronouns joined by the conjunction and. It is the and which makes the subject plural in most cases.

 The secretary and the treasurer were at the meeting.

Note the presence of the before treasurer in the sentence, an indication that there is more than one person.

There were two people at the meeting, so the subject is plural. Therefore, a plural verb were is required.

 It will be unfortunate if fate and health force him to retire.

This is a compound sentence because it has two nouns as the subject of the subordinate clause. Therefore, the verb must be plural.