AUXILIARY VERBS

          

Category 1:  be, have, do

                      

These forms of to be, to have, and to do are used before the main verb.

Their purpose is to change time or emphasis.

                   

Unlike other structure words, these auxiliary verbs

1.  can have inflectional endings (-s, -ing, -ed, -en)

2.  can also function as main verbs.

 

            

         

Category 2: Modal auxiliaries

The list below shows all of the modal auxiliaries:

Present

can

may

will

shall

must

Past

could

might

would

should

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Unlike the auxiliaries  be, have, and do, modal auxiliaries

1. do not use inflectional endings (-s, -ed, -ing, -en)

2. cannot function as main verbs.

            

 

When a verb phrase uses both kinds of auxiliary verbs, the modal auxiliary always precedes the be, have, or do auxiliary.