The document discusses the past perfect continuous tense. It explains that the past perfect continuous is used to show that a situation continued in the past until another past situation. It provides the example "I'd been doing language works all weekend long so I decided to have a break at Patty's house." The document also notes that the past perfect continuous is used in reported speech, and provides examples of sentences using this tense. It concludes by stating this tense is often used with certain words or phrases.