The verb and the subject within a sentence must agree in number. Thus, a singular subject takes a singular verb and a plural subject takes a plural verb. In order to identify the subject and the verb to ensure that they agree in number, first find the verb. The subject will be whatever is “doing” the verb.

There are four main times when subject verb agreement errors occur.

1. Words between the subject and the verb

When prepositional phrases are between the subject and the verb writers sometimes choose a verb that agrees in number with the noun within the prepositional phrase rather than the subject. Always choose the subject.

Example:

Incorrect: The balls in the park seems to have disappeared.
In this sentence balls is the subject, park is a noun in the prepositional phrase, and seems is the verb. The sentence must be changed so the verb and subject will agree in number.

Correct: The balls in the park seem to have disappeared.

2. Verb preceding the subject

When the verb comes before the subject ensure that the verb agrees with the subject. Signaling words that the verb will precede the subject are found at the beginning of the sentence and include the following: here, there, who, what, where, and which.

Example:

Incorrect: There is a lot of places to shop.
In this sentence the verb is precedes the subject places.

Correct: There are a lot of places to shop.

3. Compound subjects are used

And 

When subjects are joined by and, a plural verb is used.

Example:

Incorrect: I bet a hot dog and a hamburger tastes good off the barbeque.
The subject a hot dog and a hamburger is plural, yet the verb tastes is singular.

Correct: I bet a hot dog and a hamburger taste good off the barbeque.

Either/or and neither/nor

When subjects are linked with conjunctions that indicate one or another, the verb must agree in number with the nearest noun.

Examples:

Incorrect: Neither my cat nor dogs likes the rain.

The closest noun to the subject, dogs, is plural so the verb must be plural.

Correct: Neither my cat nor dogs like the rain.

Compounds with positives and negatives

When subjects have both a positive and negative form, the verb must agree in number with the positive part of the subject.

Example:

Incorrect: It was the speaker’s background and not his ideas that have provoked the riot.

The speaker’s background (singular) is what provoked the riot, so the verb must be singular.

Correct: It was the speaker but not his ideas that has provoked the student riot.

4. Indefinite pronouns are used

Indefinite pronouns replace a noun with an unspecified amount. Because no specific plural amount is given, indefinite pronouns always take a singular verb. The following are examples of indefinite pronouns: one, anyone, everyone, nobody, somebody, everybody, nothing, everything, something, each, either, neither.

Example:

Incorrect: Everybody at school are intelligent.
Everybody is an indefinite pronoun, so it must take a singular verb.

Correct: Everybody at school is intelligent.

Practice: Subject-verb agreement

Identify the verbs and subjects in the following sentences. Then correct errors in subject-verb agreement.

1. The content of the two courses are similar.

2. Developing my organizational skills and improving my people skills is what I need to do to get a job.

3. These hobbies give you great joy and makes for a happy life.

4. One pair of brand name shoes I own are Nike.

5. I like the style of this shirt, but the arm length and the hem is too long.

6. The audience members already know what the author is trying to say and is not very interested.

7. Writing the first paragraph, including the topic sentence and the thesis statement, are the hardest things for me to do.

8. At the Tower, all forms of exercise takes place inside the gym.

9. Being economical and environmentally friendly is important for a company today.

10. One of the most striking examples of poor workmanship and inferior materials are the new subdivision on Main Street.