Verbs are parts of speech that are vital to the study of the English language. They express some existence, feeling or action. Verbs that are limited by the number and person of their subjects are called main verbs and main verbs come in two kinds: finite verbs and non-finite verbs.
Finite verbs are dependent on the number and person of the subject and also on the tense. For example, ‘he reads’ and ‘I read’ are sentences where the verb ‘read’ changes according to the person, ‘he reads’ and ‘they read’ are sentences where the verb changes according to the number, and ‘he reads’ and ‘he is reading’ are sentences where the verb changes according to the tense.