This document discusses prepositions and prepositional phrases. It begins by defining a prepositional phrase as containing a preposition and the object of the preposition. It then lists many common prepositions used in English and examples of multi-word prepositions. The document explains how to identify prepositional phrases in sentences by finding the preposition and determining its object. Finally, it states that prepositional phrases function as adjectives or adverbs in a sentence, modifying nouns or pronouns as adjectives or verbs and other parts of speech as adverbs.