Marie's favorite event is swimming.
swimming is the gerund and I think that it is used as either a DO or a predicate nominative. I'm leaning toward PN because it renames the event?
Correct -- very nice!
You are correct that "swimming" is a gerund in the sentence "Marie's favorite event is swimming." Gerunds are formed by adding the suffix "-ing" to a verb, and they function as nouns in a sentence. In this case, "swimming" is the subject complement or predicate nominative.
To determine if "swimming" is functioning as a direct object (DO) or a predicate nominative (PN), we need to analyze the structure of the sentence. The subject of the sentence is "Marie," and the verb is "is," which is a form of the verb "to be."
In this sentence, "swimming" follows the verb "is" and renames or identifies the subject "Marie." It complements and completes the meaning of the subject by stating what Marie's favorite event is. Therefore, "swimming" is a predicate nominative.
To summarize, "swimming" is a gerund functioning as a predicate nominative in the sentence "Marie's favorite event is swimming" because it renames or identifies the subject "Marie."