I’m wondering how I can structurally determine when a verb is being used as a copula and when it is not. Specifically, is the verb “appear” followed by a verb NECESSARILY a copula (i.e., linking verb)?
One of my references (“An A-Z of English Grammar & Usage”, Longman, p.271), describes the following pattern for linking verbs:
Other patterns typical of linking verbs
(D) SUBJECT + VERB + TO BE + COMPLEMENT
However, I cannot find a source that says that “appear” followed by any verb (such as in the following example) is always a linking verb:
Sarah appeared to have won.