499. An adjective may be modified by an infinitive ([§ 321]).

500. Adjective and adverbial clauses are very common as modifiers of modifiers (cf. [§ 496]).

CHAPTER VI
INDEPENDENT ELEMENTS

501. A word or group of words that has no grammatical connection with the sentence in which it stands is called an independent element.

Independent elements are of four kinds,—interjections, vocatives (or nominatives by direct address), exclamatory nominatives, and parenthetical expressions.