33a Match verb forms with third-person singular subjects.

To make a verb in the present tense agree with a third-person singular subject, add -s or -es to the base form.

image A vegetarian diet lowers the risk of heart disease.

image What you eat affects your health.

In the preceding example, the subject is the noun clause what you eat. The clause is singular, so the base form of the verb affect takes an -s.

To make a verb in the present tense agree with any other subject, use the base form of the verb.

image I miss my family.

image They live in another state.

Have and be do not follow the -s or -es pattern with third-person singular subjects. Have changes to has; be has irregular forms in both the present and past tenses (32a).

image War is hell.

image The soldier was brave beyond the call of duty.