Use these patterns only! (Except for numbering kings, etc.)
83. Nouns that function as adjectives.
Often two nouns occur together; the first noun describes the second noun, that is, acts as an adjective. Adjectives never changer form, singular or plural.
noun + noun
He is a foreign language teacher.
He is a mathematics teacher.
What's their telephone number?
Don't use possessive form for the first noun (such as "language's"). Don't use plural form for the first noun (except for some combinations such as "sales tax", "sports-car", etc.)
84. Hyphenated adjectives.
Usually number appears as the first in a series of hyphenated adjectives. Each word in a hyphenated adjective is an adjective and doesn't changer form, singular or plural.
A sixty-year-old employee may retire.
A two-door car is cheaper than a four-door model.
A three-minute call costs less than a dollar when you dial it yourself.
His house is six-storied.
Don't use plural form for any of the adjectives joined by hyphens ("-");
-ed forms usually don't occurs in hyphenated adjectives (except for the "storied": His house is six-storied.)
85. -ed and -ing adjectives.
An -ing adjective usually expresses cause; it's derived from an active verb. An -ed adjective usually expresses result; it's derived from a passive verb.
