Can a prepositional phrase be either the sub or obj of a sentence?

Question

I had a discussion a while back with this guy who had just finished college. He reported that he had successfully argued down his professor on the point of a prepositional phrase, itself, can be the subject or object in a sentence. I argued on the side of the prof. that it COULD be, of course. I want your opinions and tomorrow I will post an addition showing my proof that it CAN be.
Thanks

General Motors made 2,345,678 cars last year.

or with prepositions as both subject and object


About 2 1/3 million cars were made by GM last year.


So I guess that prepositional phrases CAN be subjects and objects in a sentence.

Answer 1

i didnt think so, i mean ok this is how i see it, the squirrell is ______ the tree. squirrell would be the subject, is is the verb and ____ the tree is the prepositional phrase