Prepositions - "of" and "for"

[DianaG875]

Hey,

I read that following "of" and "for" should be a noun. However, is it grammatically (and GMAC-wise) correct to place adjectives between "of" and "for" and the noun itself? How about articles - a/an/the?
How strict is it?

Thanks!

[StaceyKoprince]

The baseline structure for a prepositional phrase is preposition + noun, but the noun doesn't immediately need to follow the preposition and you can have adjectives, articles, and similar words that modify the noun:
I bought food...
...for the cat (article = the)
...for the black cat (adjective = black)
...for the black cat with the white tail (noun modifier [describes cat] = with the white tail)
...for the black cat sleeping by the fire (noun modifier [describes cat] = sleeping by the fire)

It can't have a clause (subject and verb), so you wouldn't say:
I bought food...
...for the cat jumps off the fence

"the cat jumps off the fence" is a clause or a complete sentence—it's got a subject and verb. Prepositional phrases are noun phrases—they don't have main verbs / actions. (Note: The "sleeping by the fire" example is not an example of a main verb. You can't say "The cat sleeping by the fire." as a complete sentence.)