This document discusses prepositions and prepositional phrases. It defines prepositions as words that show the relationship between nouns/pronouns and other words in a sentence. Prepositions are usually short words and there are over 60 common prepositions. The noun or pronoun following a preposition is called the object of the preposition. A preposition and its object form a prepositional phrase, which does not contain a verb. Prepositional phrases can be placed at the beginning, middle, or end of a sentence. The document also discusses pronoun usage in prepositional phrases and contains an activity where the reader finds prepositions around the room and writes sentences using them.