There are three main auxiliary verbs in English: to be, to do, and to have.
The most common auxiliary verbs used are in the to be and to have forms. These verbs help you express time by forming the various tenses. There are other auxiliary verbs, such as can, could, may, might, shall, should, must, will, would. We will focus on the to have verb in this exercise. This verb is used to express time.
The verb have is an irregular verb. The present form is shown above. Used as an auxiliary verb, it is used to form the present perfect.