Function Words

What is an auxiliary?

An auxiliary is a short verb prefixed to one of the principal parts of other verb, to express some particular mode and time of being, action, or passion.  The auxiliaries are do, be, have, shall, will, may, can, and must, with their variations.


The most common auxiliaries are forms of be and have.  These may be distinguished from their homophones (be employed as linking verb, have as a transitive verb) by their occurrence in close conjunction (actual or understood) with the participles of other verbs (endings in –ed, –n, en, ing).


I was asked to come. – Were you? (asked?)

He has seen it.

They were going.


Notice, however, that some former participles are now fixed as adjectives.  The forms of be that follow are to be identified as linking verbs, not auxiliaries.


She is charming.

That book was interesting.

This tape is broken.


Forms of be and have identify as (modal) auxiliaries when followed by infinitive (to+ verb stem).


You are to report at 0740.

He had to go home.


Had+better forms modal auxiliary (of obligation) when followed by the simple form of the verb.


You had (transitive) better clothes last year.

You had (m. aux.) better go now.


Auxiliaries other than be and have may be partially identified in the following ways.


1.They occur in close conjunction (actual or understood) with the simple form of other verbs.

I can go – Can you? (Go?)

We should leave.

I must write him.


2. They are often followed directly by not, or combine with it to form the contraction n’t. (But non-auxiliary forms of be and have do this too.)

I could not help it.

I couldn’t help it.

We didn’t need any.


3. In conjunction with the participles of other verbs and auxiliary forms of be and have, they occur as the initial element of complex verbal structures.

I may be having a party.

I will have lived here 6 years next October.

Could he have been going downtown?


You will find more about function words here see:

Function Words

Question words

March 21, 2015