The verb forms of be, do, and have can be used either as a main (full) verb or an auxiliary verb. The following examples show these verbs used as auxiliary verbs.

1. "Be" used in progressive sentences. Example : I am taking a bath. / She is preparing dinner for us.
2. "Be" Used in passive sentences. Example : I was given a free meal. / He was seen by fans at the airport.
3."Do" Used in negative sentences. Example : I do not know the truth. / She doesn’t agree with me.
4."Do" Used in questions. Example : Do you want to have another one? / Did he finish his homework?
5."Have" Used in perfect sentences. Example : We have done a lot so far. / She had been queen of the town.