Rhetoric and Composition/Lack of agreement between subject and verb

Subject agreement is that the agreement of subjects and verbs

Examples

 * Singular: The whale, which doesn’t mature sexually until six or seven years old and which has only one calf per year, is at risk for extinction because it reproduces so slowly.
 * Plural: During election season, several civic groups sponsor public debates in which candidates present their views and audience members ask questions.
 * Singular: Digging a few inches into the dunes, even at 750 feet above the valley floor, reveals wet sand.
 * Plural: The dunes comprise small rocks and dry, sandy soil that constantly form strange designs under the ever-present wind.

What is subject-verb agreement?
Subject-verb agreement is something most native speakers know pretty automatically, but we can make mistakes when writing, especially when several words separate a particular subject and verb. As you can see in the following examples, “of” phrases can be misleading, too. The trick is to find the “root” noun: the one actually performing the action of the verb. There are two easy ways to spot the subject of a sentence: 1) Find the verb and ask the question, "Who or what is performing this act?" 2) Cross out all prepositional phrases. These simply tasks should lead you right to the subject of the sentence.

Examples

 * Characteristics of the middle child often include an equitable temperament and high feelings of security and self-esteem.
 * The opportunity cost of loaning out the funds is usually reflected in the interest rate.
 * A certain percentage of the cars produced by major manufacturers meets stricter emission standards in order for the company to sell their products in regulated regions.

Other guidelines
Other guidelines for making subjects and verbs agree include:
 * Noncount nouns — those that don’t have a singular or plural form, such as furniture, baggage, poetry, melancholy — take a singular verb.
 * Two or more singular nouns joined by an “and” take a plural verb: A timely, relevant topic and an environment of trust produce a good class discussion.
 * When two nouns differing in number are joined by “or,” the verb should take the form of the noun closest to it: Most viewers of the painting assume that either the monkey’s antics or the handler’s chagrin causes the young men’s laughter.

If you struggle with problems in subject-verb agreement, leave time to edit your paper once through just for that error: go through each sentence, underlining each subject and verb pair and checking that they agree.