It seems that phrases are viewed in two ways: one of function; other of construction.
It somehow dawned upon me that, barring the "infinitives" all prepositial phrases(PPs), whatever be its components, are mostly adverbials in function, if not used as a subject in a sentence. Here are certain representative, though not exhaustive, examples to drive home my point.
He came 'to me'.
This will last 'for ever'.
He is 'about to go'.
He is ignorant of 'how to swim'
It depends 'on how you do'
What do you know 'regarding this'.
The book is 'on the table'.
So is it correct to view PPs as mostly adverbials?
However, such PPs, when governing a noun/pronoun do they become adjctivals?