The fundamental principle of syntax requires the verb to agree with its…

Concept

Subject–verb agreement is a grammatical concord rule. A finite verb changes form according to grammatical features carried by its subject, so the subject and verb must share the relevant agreement features.

Application

In standard English, the relevant features are number (singular or plural) and person (first, second, or third). For example, “I am,” “you are,” and “she is” show person distinctions, while “the child plays” and “the children play” show number distinctions.

Contrast

• Gender and case classify nominal forms and grammatical roles.

• Mood and voice describe modality and participant structure.

• Tense and aspect describe time and the temporal presentation of an event.

Result

Therefore, the verb agrees with its subject in number and person.