Other Phrases

[@mrinmoybrahma8548]

Some of the boys are playing
In this sentence,
(Some of the boys) is a subject & Noun Phrase.
(Some, the ) are determines & (boys) is a head noun.
but (Of) is used as what? Is this an Adjective?
I need an explanation, why this is an adjective?

[@KSAstro.]

( Some of ) adjective