Modal Auxiliary Verbs
(Present)
The most common auxiliary verbs are "be," "do," and "have", and you may also use
these verbs on their own. Other common auxiliaries are "can," "could," "may,"
"might," "must," "ought," "should," "will," and "would." A verb like these is called a
modal auxiliary and expresses necessity, obligation, or possibility.
Most common
Auxiliary Verb
Present
I do work.
I have worked
I have been working.
Can is a auxiliary
Verb
We use can to
•talk about possibility and ability
• make requests
• ask for or give permission
Modal Auxiliary Verbs
Past
The highlighted word in each of the following sentences is a modal auxiliary
Example
Zora was pleased to learn that she could take several days off.
The small freckled girl told her neighbors that she would walk their dog for an
appropriate fee.
Estructure of could
Subject + could + main verb
Use of Could
Could: Past Possibility or Ability
We use could to talk about what was possible in the past, what we were able or
free to do:
• I could swim when I was 5 years old.
• My grandmother could speak seven languages.
• When we arrived home, we could not open the door.