1) The document discusses the past continuous tense, which is formed using was/were + verb + -ing to describe an action that was ongoing or in progress at a specific time in the past.
2) Some common uses of the past continuous tense include describing background events that were happening when another action occurred or describing two simultaneous ongoing actions in the past.
3) Time expressions like "at 8 o'clock", "when", "while", etc. are often used with the past continuous tense to specify when the ongoing past action was happening.