Rules for writers, Tenth edition - Diana Hacker, Nancy Sommers 2021

Learn to recognize the standard subject-verb combinations
Make subjects and verbs agree
Grammar

In the present tense, verbs agree with their subjects in number (singular or plural) and in person (first, second, third): I sing, you sing, he sings, she sings, we sing, they sing. Even if your ear recognizes the standard subject-verb combinations presented in 21a, you will no doubt encounter tricky situations such as those described in 21b—21k.

21a Learn to recognize the standard subject-verb combinations.

This section describes the basic guidelines for making present-tense verbs agree with their subjects. The present-tense ending -s (or -es) is used on a verb if its subject is third-person singular (he, she, it, and singular nouns); otherwise, the verb takes no ending. Consider, for example, the present-tense forms of the verbs love and try, given at the beginning of the chart on page 182.

The verb be varies from this pattern; it has special forms in both the present and the past tense. These forms appear at the end of the chart.

If you aren’t sure of the standard forms, use the charts on pages 182 and 183 as you proofread your work for subject-verb agreement. You may also want to look at 27c on -s endings of regular and irregular verbs.

SUBJECT-VERB AGREEMENT

Present-tense forms of love and try (typical verbs)

Present-tense forms of have

Present-tense forms of do (including negative forms)

Present-tense and past-tense forms of be

WHEN TO USE THE -S (OR -ES) FORM OF A PRESENT-TENSE VERB

✵ EXCEPTION: Choosing the correct present-tense form of be (am, is, or are) is not quite so simple. See the chart on the previous page for both present- and past-tense forms of be.

✵ NOTE: Do not use the -s form of a verb if it follows a modal verb such as can, must, or should or another helping verb. (see 28c.)