488. An adjective may serve as a predicate objective. Thus,—

Care should be taken not to confuse adverbs with adjectives in -ly serving as predicate objectives.

After the passive, a predicate objective becomes a predicate nominative ([§ 489]).

3. THE PREDICATE NOMINATIVE

489. A substantive standing in the predicate, but describing or defining the subject, agrees with the subject in case and is called a predicate nominative ([§ 88, 2]).

A predicate nominative is often called a subject complement or an attribute.

The predicate nominative is common after is and other copulative verbs, and after certain transitive verbs in the passive voice.