Linking verbs are verbs that link the subject to the predicate so that more Information about the subject can be provided in the predicate. Examples are seem, appear, look, feel. An important point is that since the predicate modifier is modifying the subject, a noun, it is an adjective, not an adverb. For this reason, the always stupid "I felt badly." is wrong. Because feel is a linking verb, the predicate modifier is an adjective, bad, not an adverb, badly.
An action verb moves action from the subject to the predicate and requires an object. There are many examples: wave, see, jump, blow, etc. The predicate will be in the object form: I wave to him. She sees them.
