They are:
used to modify:
The three articles, a, an, and the (sometimes referred to as determiners) always function as adjectives in a sentence.
And there are three categories of adjectives:
A descriptive adjective describes a quality of the noun the adjective modifies.
A proper adjective is formed by using a proper noun.
Predicate adjectives follow the noun and are connected to the noun by a linking verb.
In the following examples, the predicate adjective follows the highlighted linking verb: