This document provides information about the proper uses of the prepositions "in", "on", and "at" as they relate to time and place. It explains that "in" is generally used for enclosed spaces and long periods of time, "on" is used for surfaces and specific days/dates, and "at" is used for precise times and points. Numerous examples are given to illustrate the different uses of each preposition in contexts involving locations, dates, times of day, activities, and states. At the end, an activity is included where the reader must choose the correct preposition to complete sentences about time and place.