In most of the examples, the predicate nominative has one or more modifiers. In the first sentence, science is modified by the two adjectives a and useful; in the second, capital is modified by the adjective phrase of Massachusetts; in the last, friend is modified by the adjective clause upon whom I can rely.

For the distinction between the predicate nominative and the direct object, see [§ 102].

490. A noun clause may be used as a predicate nominative ([§ 386]).

491. An infinitive may be used as a predicate nominative.

The infinitive may have a complement or modifiers. In the second and third examples, it takes an object; in the fourth it is modified by an adverb.

4. THE PREDICATE ADJECTIVE

492. An adjective in the predicate belonging to a noun or pronoun in the subject is called a predicate adjective.