Primary Auxiliary Verbs are the different forms of the verbs Do, Be and Have helping the main verbs to complete their meanings in different tenses.
- She does not know my name.
- Little Alan did not kick the ball.
- The cattle were not grazing by the side of the canal.
- Who has finished his work?
- The poor man had not eaten anything for two days.
In the above sentences, does, did, were, has, and had are the primary auxiliary verbs associated with the main verbs know, kick, grazing, finished, and eaten respectively
Primary auxiliary verbs do not have any meaning of their own. They decide the tense of the main verbs.