The document discusses the simple past tense in Spanish. The simple past is used to talk about actions that occurred in the past. To form the simple past of regular verbs, the ending "-ed" is added to the base form of the verb. However, some verbs are irregular and do not follow this pattern. Auxiliary verbs like "did" and "didn't" are used to ask and negate actions in the past tense. While most verbs follow a set of rules, some like "be", "have" and "can" function differently in the simple past.