This document discusses different types of prepositions in English grammar. It defines prepositions as words used before nouns to indicate their relationship to other words in the sentence. Prepositions are divided into categories based on their use - of place, time and movement. They are also classified based on their structure as simple one-word prepositions, double prepositions that combine into one word, compound two-word prepositions, and participle prepositions formed from verb participles. Examples are provided for each type of preposition along with exercises for students to practice identifying and using different prepositions correctly.