The document discusses the use of prepositions in English. It provides examples of how to use the prepositions "in", "on", and "at" to indicate time, dates, seasons, ages, centuries, and more. It then lists additional common English prepositions such as "about", "above", "across", "after", "against", "along", and others, providing examples of how each preposition is used. The content was retrieved from an English learning blog that offers tips, lessons, vocabulary lists and more resources for learning English.