An adjective phrase is built around an adjective. It may consist of one word, as in salty, or include words that change its degree or complete its meaning, as in very salty and proud of it.
Where does the adjective phrase end?
Salty is an adjective phrase with just its adjective head.
Proud of it is one adjective phrase: the PP is a complement of proud.
What fills the subject-complement slot in each?
Proud of it is one adjective phrase: the PP completes proud.
Pleased fills the same slot as an adjective phrase of one word.
The replacement occupies the same subject-complement slot. Replacing only proud would leave of it attached to an adjective that does not take it. That supports the boundary in this example: the prepositional phrase belongs with proud, not directly with seemed.
one head, more material
A degree word stays inside the phrase too
Dangerously modifies narrow inside the adjective phrase; the whole phrase is the subject complement.
Dangerously changes the degree of narrow; it does not describe the becoming. The two words form an adjective phrase whose complete phrase is the subject complement. In other sentences an adjective phrase can instead premodify a noun, so its form and its larger job remain separate questions.
Build the phrase around the adjective.
A degree word such as very belongs with the adjective it modifies. A following prepositional phrase can also belong inside the adjective phrase when it completes the adjective’s meaning. Those relationships show where the phrase begins and ends.
Ten sentences from this lesson, one decision at a time.