Verbs

The subject of a sentence is determined by a verb .Verbs can be grouped into three categories (1).Action Verbs (2).Linking verbs or state of being verbs (3).Auxiliary or helping verbs.

(1).ACTION VERBS demonstrates an action.And this type of nouns are majorly used.

• The girl sang loudly. 

• Sir shouted at him.

(2).LINKING OR STATE OF BEING VERBS tells the condition of someone or something.

• He was sick.

• I am so happy for nothing.

(3).AUXILIARY OR HELPING VERBS help describe the main verb.There are nine helping words mainly used,they are never the main verb.
These helping verbs are:

1. May
2. Might
3. Must
4. Can
5. Could
6. Will
7. Would
8. Shall
9. Should

Lets have a glance at some examples,where the main verb is highlighted while the helping verb is underlined.

• That girl might sing the song. 

• Mam could beat her.

The main verb and the helping verb together is known as the complete verb.There are three verbs Be,Do,Have,which can be used either as a main verb or helping verb depending on their usage.
Be forms include Is,Are,Was,Were,Being.Been.Do forms include Does,Did.Have forms include  Has,Had.
As Main verb:

• She is a nice friend of mine.

• He did this. 

As Helping verb:

• She has done this .

• He has written another article.