Yes
It is an action verb.
Yes, returned, the past tense of return, is an action and therefore a verb.A verb is a word that describes an action (run, walk, etc), a state of being (exist, stand, etc) or occurrence (happen, become, etc).
began is an action verb, not a linking verb.
"Sent" is an action verb. It shows an action, such as "she sent an email."
Yes, "return" can be used as a noun to refer to the action or process of coming or going back to a place or condition.
what follows a linking or action verb
It is an action verb.
action verb
Action verb
Action verb
An action verb