The boy is asleep.

I feel faint.

3. Position: predicative only

There are some adjectives which only usually occur in the predicative position, as complements of be or other link verbs. For instance, you can say He felt glad. but wouldn’t normally talk about a glad person.

Adjectives which usually occur in the predicative position include those which describe feelings, such as afraid, content, glad, ready, sure, sorry and upset, e.g.:

She felt afraid. but not, e.g.: an afraid girl

My daughter is upset. but not, e.g.: my upset daughter

They also include a group of adjectives with prefix a-, such as asleep, alive, alone, ashamed, awake, aware, e.g.:

I like being alone. but not, e.g.: I like being an alone person.

The baby’s asleep. but not, e.g.: the asleep baby.

2. Position: attributive only

There are some adjectives which can only be used before a noun, in the attributive position. For instance, we talk about the main problem but cannot say, the problem was main.

Adjectives which occur only in the attributive position are generally those which identify something as being of a particular type. For instance, we can talk about a financial decision where financial distinguishes this from other types of decision, e.g.: medical, political. This group of adjectives are often referred to as classifying adjectives, and rarely occur in the predicative position unless we specifically want to emphasise a contrast, e.g.:

a chemical reaction not, e.g.: a reaction which was/is chemical

the phonetic alphabet not, e.g.: the alphabet is phonetic

It was an indoor pool. not, e.g.: The pool was indoor

countless, eastern (northern, etc.), existing, neighboring, atomic, indoor, occasional, digital, introductory, outdoor, maximum, absolute,complete, entire, outright, perfect, positive, pure, true, real, utter, total;

Predicative adjectives:

(A) afraid, asleep,alive, aware, alone, content, due, ready, unable, glad, sorry, well, ill, sure;

(B) adjectives that describe size or age, such as deep, long, tall, wide, high, old, thick.