English has three primary auxiliary verbs- do, be, and have. All three take part in the formation of various grammatical constructions, but carry very little meaning themselves. For example, the primary auxiliary be is used to form the progressive, as in bill is dancing.
modal auxiliary- Modals auxiliary verbs are a very complex area of English grammar, so in this quick guide we will not be able to go into much detail, but we will at least get an overall idea of what their function is in a sentence. In an earlier section of this guide we looked at how the verb phrase can be broken down into its constituent parts and we noted that one of these parts was called a modal auxiliary verb.