Is finish an action verb or linking verb?

Answer 1

The verb 'finish' can be an action verb or a linking verb depending of its use. Examples:

Linking verb: You will finish as first. (the object first is a form of the subject you)

Action verb: You will finish your broccoli. (the object broccoli is not the same as the subject you)

Answer 2

The verb 'finished' is the past tense of the verb to finish.

The verb 'finish' (or finished) can be transitive or intransitive.

Examples:

When you finish dinner, you may go out. (transitive, direct object is 'dinner')

I finished dinner already. (transitive, direct object is 'dinner')

You may go out when you finish. (intransitive, no direct object)

When you've finished, you may go out. (intransitive, no direct object)