Auxiliary verbs
An auxiliary verb (“helping” verb) is combined with the principal verb to form certain tenses or moods. (See also the modal verbs, which nuance the meaning of the verbs they accompany.) The only true auxiliary verbs in English are “to be,” “to have,” and “to do.”
“To be” is an auxiliary verb for the progressive teneses (See the present progressive, the past progressive, the future progressive):
- I am going home.
- She was fishing with her father.
- We will be calling on you later.
“To have” is an auxiliary verb for the perfect tenses, including the present perfect, the present perfect progressive, the pluperfect, the future perfect, the past conditional:
- We have finished.
- They hadn’t waited for us.
“To do” is an auxiliary verb for making questions and negations in both the present simple and the preterit :
- Do you have any money?
- Did you hear me?
- He doesn’t want to help us.