Printable version of Subject-verb agreement (PDF).
Subject-verb agreement involves using the right verb form for the noun that holds the subject position in your sentence. If the grammatical subject of your sentence is singular, you use a singular verb form; if it is plural, you use the plural verb form. Subjects and verbs are said to disagree when verb endings do not correspond to the subject.
Personal endings for regular English verbs:
You (plural) walk
Note that the only time you need a different ending is with the third person singular form. You also need to consider different forms with some common irregular verbs:
You (plural) are
You (plural) have
These common irregular verbs are especially important because they are also auxiliary verbs:
She is walking to school.
She has walked to school.
They are walking to school.
They have walked to school.
Common Errors in Subject-Verb Agreement
Errors in subject-verb agreement occur much more frequently when sentences become more complicated. Be careful of the following tricky situations:
When there are several words between the subject and verb. The tendency is to make the verb agree with the closest noun, which is not correct.
e.g., The reliability of many standard intelligent tests have been challenged in recent years.
The subject of this sentence is reliability so the verb should be has been challenged.
When the subjects are compound, that is, when two singular subjects are joined by and (A and B) to form a plural subject.
e.g., The high cost and extreme difficulty of implementing the project was cited in the explanation of its cancellation.
The subject here is high cost and difficulty (two things) so the verb should be were cited.
When the subjects are who, which, or that (the first words in adjective clauses).
e.g., Elena is one of the many students who has benefitted from the services of the Writing Centre.
In this sentence, the word who is a pronoun that refers to plural students, so the verb should be have benefitted.
When the subject comes after the verb as in inverted sentences.
e.g., Under the table was several empty beer bottles and various dirty socks.
In this sentence, although the subject empty beer bottles and various dirty socks comes
after the verb was, it is still plural so the verb should be were.
When the subject is a collective noun (team, audience, class, family, etc.).
Collective nouns are especially tricky because they can be singular or plural, depending on the context.
Collective nouns are followed by singular verbs when the members of the group are functioning as a single entity, and by plural verbs when they are functioning as individuals within the group.
e.g., The class is writing the exam.
In this case, the class is functioning as a unit, so the verb is singular.
e.g., After the exam, the class go their separate ways.
In this case, the individuals in the class are doing different things, so the verb is plural.