Butterfly is beautiful.
Main verbs can stand alone. =x
Run, eat, work we
Auxiliary verbs, also called helping verbs,
serve as support to the main verbs( Have, has,
had, do, does, did, be, am, is, are, was, were,
been, being, should, could, would, will, might,
can, may, must ,ought(to), shall).
fppt.com