The document explains the past continuous tense, which is used to describe actions that were ongoing or in progress at a specific time in the past. Examples are provided such as "I was playing badminton at this time yesterday" and "She was cycling at 9:00am yesterday." A table illustrates how the past continuous is formed using was/were + a verb with -ing. The document then provides an exercise for learners to practice using the past continuous tense to describe what different people were doing when a fire broke out in their building.