Prepositional phrases?

I am doing an assignment and have not been in school for a number of years. I am having trouble with my communication strategies class and pretty much have to start from scratch at learning this stuff. I am having trouble with prepositional phrases. For instance, the following 2 sentences are examples of some of my questions and I have to say whether they are prepositional sentences or not.
1. Tell the guests (to park their cars) behind the restaurant.
2. He knows he is supposed to come home (before noon).
3. He now drinks his coffee (with sugar).
4. I think Gary went (into the conference room) with the other managersNow I think they all sound like prepositional phrases and so I am not sure I am getting this. Any good way to figure this out?
I have 3 pages of these questions. Thanks!

Sorry the last one # 4 end with "the other managers". Somehow I missed the period and new sentence

#1 is not a prepositional phrase. Prep. phrases do not contain verbs.

If you read the sentence and you can not leave the phrase out it is not a prep. phrase. If you read 2-4 you will notice that if you leave the phrase off the sentence still makes sense.

All of them are prepositional phrases.

These are the prepostitioons:
with, on, for, after, at, by, in, against, instead, of, near, between, to, off, under, down, below, through, over, up, according, to, abraod, across, beyond, aboiut, before, behind, within, without, admist, among, around, above, towards, not, with, standing, into, of, like.


Hope I helped.

Not completely sure what you mean by prepositional sentence. But, I can tell you that NOT all four of your examples contain prepositional phrases.

Prepositional phrases are phrases started with a preposition. Examples of prepositions are: above, about, around, by, behind, below, before, down, in, to, into, with, without, under, over, beside, between.

Prepositional phrase can be removed from a sentence and the sentence will still make sense.
Try to remove the part in ( ) from the first sentence
Tell the guests behind the restaurant. Not exactly what the sentence means. "To park" is an infinitive verb form and not a preposition in the case.
(Behind the restaurant is a prepositional phrase, but I assume we are talking only about the words in parenthesis)

I believe that words in parenthesis in the 2,3,4 sentences are prepositional phrases.