The document discusses the past simple tense in Russian, which is used to describe actions that occurred in the past. It notes that regular verbs form the past tense by adding an "-ed" ending, while irregular verbs have varying past tense forms. Examples are provided of common time expressions that indicate the past tense, such as "yesterday" and "last week." It also explains how to form yes/no questions and negative statements in the past simple tense using the helping verb "did."