The correct statement for the base forms of verbs is that when the
subject of a sentence is singular, add -s to the base form. For example,
he runS every day. If you add to to the base, you won't get an
adjective, but rather an infinitive form of a verb. -Ed is added to
regular, not irregular verbs. Base form is used with plural subjects -
we run every day: run is the base form.