Helping verbs are attached to the main verb to help describe when the action will occur.
is
am
are
was
were
be
being
been
can
could have
could have been
had
has
has been
have been
must have
must have been
ought to
shall
shall be
should have
should have been
used to
will
will be
would have
would have been
Linking verbs express a state of being rather than action. Below is a list of linking verbs.
grow
remain
seem
stay
was
were
Language Arts: Linking Verbs and Helping Verbs