A preposition is a word that indicates the relationship between other words in a sentence. Common prepositions in English include of, to, in, for, with, on. A prepositional phrase consists of a preposition and its object. Examples of prepositional phrases include "on the raft", "to Norfolk, Virginia", and "below the sink". Prepositions show relationships of time, place, and other connections between nouns, pronouns, and phrases in a sentence.