verb agreement

In English, subjects and present-tense verbs must agree in number: both must be either singular or plural.

If the subject is a singular noun or third-person pronoun, the verb will end in an added s (or es):

• That bird chirps so loudly that it wakes me up every morning.
• Josée catches trout in the lake near her cottage.

Note that a plural verb does not have an added s (or es):

• Those birds chirp so loudly that they wake me up every morning.
• Josée and Alain catch trout in the lake near their cottage.

Remember this rule: when we add s or es to a verb, we make it singular.

The s-ending rule also holds true for the irregular helping verbs be, do and have—the singular forms of these verbs all end in s:

• Only one light is flickering.
• That frog has been croaking for hours.
• Background noise does not bother me.

Tip: Usually, if there is an s on the subject, there won’t be one on the verb, and vice versa:

• The bird chirps. [s on the verb, none on the subject]
• The birds chirp. [s on the subject, none on the verb]