The document discusses the past continuous tense, also known as the past progressive tense. It provides examples of how to form the past continuous tense using "was/were + verb+ing" and discusses how to add "not" to form the negative. It also gives examples of asking questions in the past continuous tense using "was/were" and answering with "yes/no". Finally, it discusses using the past continuous tense to describe two parallel actions happening in the past or an interruption by another past action.