Auxiliary verbs are known as helping verbs because they add functional or grammatical meaning to the clauses in which they appear.
There are three main auxiliary verbs: have, be and do.
A main verb indicates an action (run, read, write, drink, etc.).
An auxiliary verb accompanies the main verb in different verb phrases but it can also stand alone, functioning as a state verb (verbs that express a state and not an action).
- Rachel has a new friend. (state verb)
- Mary has finished her exams. (auxiliary verb)
- John does his homework regularly. (action verb)
- Mary doesn’t study every day. (auxiliary verb)
- Mary is happy. (state verb)
- John is studying at the moment. (auxiliary verb)