How to know if a word is an auxiliary verb ​

An auxiliary verb (or a helping verb as it's also called) is used with a main verb to help express the main verb's tense, mood, or voice.

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1)They appear in the following forms:

2)To Be: am, is, are, was, were, being, been, will be.

3)To Have: has, have, had, having, will have.

4)To Do: does, do, did, will do.

answer; (you have the right of way);