Is "did" a linking verb?
"Did" is not a linking verb.
"Did" is a helping verb.
I can't elaborate too much on this, but I hope I helped (:
No, did is an action verb because did expresses an action.
Linking verbs do not express actions such as hugging or throwing.
Linking verb example:
She is brilliant. (She is the subject and a pronoun, is is the linking verb and simple predicate, brilliant is the subject complement.)
Action verb example:
She did her homework. (She is the subject and a pronoun, did is a transitive action verb, her is a possessive pronoun/adjective, homework is a noun and the direct object of the sentence.) Did is an action; she did (wrote, completed, read, etc.) her homework. She physically did something.