PREPOSITIONS show relationships between nouns and pronouns,

                             it is BESIDE Tom, but BEHIND me, it is UP there

         create prepositional phrases,

       FOR an hour, IN ABOUT two hours, AROUND there

           are required with certain verbs,

       argue OVER, think ABOUT, dream OF, apologize FOR

                    and certain adjectives,

               afraid OF, angry WITH, worried ABOUT

     and combine with verbs as particles to form phrasal verbs

              to break AWAY,  DOWN,  IN,  OFF,  OUT,  UP





Prepositions are the most difficult part of speech in English and most languages. While they act as glue between words they are arbitrary and only sometimes make sense. Additionally, when they work with verbs to create phrasal verbs they act more as adverbs.

In English we say to dream OF something, but in Spanish you dream WITH something.