In English, the predicate verb must be consistent with the subject's person and singular and plural, that is, the singular subject must use singular predicate and the plural subject must use plural predicate.

She is a student.

They are students.

Is in the first sentence is a predicate verb, which is singular.

Are in the second sentence is a plural predicate verb.

The so-called predicate verb is a verb used as a predicate.

Extended data:

Generally speaking, a sentence without a predicate is incomplete. Because predicates explain the subject, examples without predicates are like headless flies, which make people feel confused and unintelligible. But predicates in some sentences can be omitted, such as exclamations. What a stupid thing (you did it)! What is in brackets is that the subject and predicate of the sentence can be omitted.

Verbs can act as non-predicate and predicate, and act as predicate, that is, predicate verbs. Predicate verbs are limited by the subject in morphological changes, which some people call the change of sum and number, and are an indispensable part of sentences or clauses.

Baidu Encyclopedia-Predicate Verb