Prepositional phrases can be made up of a million different words, but they tend to ... This whole phrase, in turn, takes on a modifying role, acting as an adjective or an ... The professor can sit on the desk (when he's being informal) or behind the ... It doesn't take a grammarian to spot a sentence-ending preposition
I believe the answer would be "is being torn down soon".
Explanation:
It's been years since I've learned about prepositional phrases (I did so in 7th grade), but from what I understand prepositional phrases complete the sentence. So, "is being torn down soon" completes the sentence. Without that phrase, the sentence would not make sense and would instead be a fragment.
