A Preposition is a word which shows relationship among other words in
the sentence. The relationships include direction, place time, cause,
manner and amount. A preposition comes before a noun or pronoun. A
preposition phrase contains a preposition and object. Prepositional
phrases are like idioms and are best learned through listening to and
reading as much as possible, Little Red Book of Prepositions is a ready
reference book with a check list of propositions.