Verb is a word used to describe an action, state, or occurrence, and forms the main part of the predicate of a sentence. Verbs are modified in form to encode tense, aspect, mood, and voice.
Classification of verbs
We may classify verbs as action/dynamic verbs, verbs of being, linking verbs, auxiliary verbs, lexical verbs, finite verbs, nonfinite verbs, regular verbs, irregular verbs and so on.
These verbs talk about what the subject is doing in the sentence. To identify them, you simply have to look for the word in the sentence that answers the question ‘what is the subject doing?’
Transitive verbs have a definite object on which, or for which the action is being performed. The action passes from the subject to the object which is direct or indirect.
Consider the sentence, 'Sheela is laughing'. The verb ‘laughing’ is describing the action done by the subject, but there is no specific object for the action. In this sentence laughing is an intransitive verb.
Verbs of being verbs
Verbs of being (forms of be - is, are, am, was, were, has/have/had been, will be) show a state of existence.
Linking verbs do not tell anything about a subject; instead they connect the subject to a subject complement which identifies or describes the subject.
Linking verbs are either verbs of sensation ("feel," "look," "smell," "sound," "taste" etc.) Or verbs of existence ("act," "appear," "be," "become,”etc.)
These verbs are also called helping verbs, as they ‘help’ the main verb to denote the actions of the subject. They help in making compound tenses of the main verb and also help in making negative statements, questions and passive voice statements.
There are two types of auxiliaries: the primary auxiliaries and the modal auxiliaries.
A lexical verb (also known as a full or main verb) is any verb in english that isn't an auxiliary verb. It conveys a real meaning and doesn't depend on another verb.
Finite verbs are those verbs that have a definite relation with the subject or noun.
Non finite verbs
A non- finite verb is a form of a verb that does not have a subject and does not indicate any tense, mood, gender and number in an independent clause or sentence. They cannot stand alone as the main verb in a sentence.
A regular verb or weak verb forms its past tense and past participle by adding -d or -ed (or in some cases -t) to the base form. These verbs do not undergo substantial changes while changing forms between tenses.
Those verbs that undergo substantial changes when changing forms between tenses are irregular verbs. They do not form the past tense by adding -d or –ed and the changed forms of these verbs are often significantly different from the originals.