The document discusses the simple past tense in English. It explains that the simple past is used to express activities or events that happened in the past. It lists common signal words that indicate the simple past, such as "yesterday" and "ago." It then provides examples of positive, negative, and interrogative sentences in both the verbal form using auxiliary verbs and the nominal form using forms of "to be." Finally, it provides a short story as an example using simple past tense constructions.