Auxiliary verbs

What are auxiliary verbs?

Basically, auxiliary verbs are function words, a type of closed class which is constituted of words
that have a grammatical function as opposed to content words , which are an open class of lexical words. An auxiliary verb is used to add functional or grammatical content to the information expressed by another verb considered to be the main verb. Auxiliary verbs are also called helping verbs

Examples:

I am writing a book.
He has done the work.
We will be there in a minute.
Would you help me with this
homework?
Can you open the door?
Did you visit New York last
holiday?
Do you like chocolate?
They must get there on time.

List of auxiliary verbs

This is a list of English auxiliary verbs:

be (am , are , is , was, were,
being ),
can,
could,
do (did , does, doing),
have ( had, has, having ),
may ,
might ,
must ,
shall ,
should ,
will,
would

Auxiliary verb or full verb?

To distinguish a full verb from an
auxiliary verb, you can carry out
the following test:

If the verb
1. allows subject-auxiliary inversion
2. and can take can take not in the negative form, then it is an auxiliary verb.

Examples:

You are going to travel to London. --
Are you going to travel to London?
You are not going to travel to iLondon.
= are is an an auxiliary verb
You see what I mean. --
*See you what I mean.
*You see not what I mean.
= see is not an auxiliary verb; it
is a full verb.

(The asterisk * indicates that the
sentence is not grammatical.)