The document discusses the past continuous tense in English grammar. It begins by defining the past continuous tense as describing a past action that was ongoing when another action took place. It then provides the formula for forming the past continuous tense using was/were + the -ing form of the verb. It provides examples and discusses four main uses of the past continuous tense: 1) describing ongoing events at a particular time in the past, 2) describing background events, 3) giving reasons/context for past events, and 4) describing repeated or ongoing events in the past. It concludes by noting that the past continuous is often used with the simple past when expressing a long ongoing action and a short action that occurred within it.