(You can learn about the past perfect continuous here.)
Practice 1: making the past perfect continuous
Complete these sentences with the word(s) in brackets using just the past perfect continuous. Remember to use contractions (I'd not I had) where possible.
Note: in questions 1 - 4 above, the past perfect simple is also possible. In question 3, the meaning is different for simple and continuous forms - he used the shampoo once (he'd used my shampoo), or many times (he'd been using my shampoo). In question 5, you need the past perfect continuous not simple, because 'had been drinking' means he had more than one alcoholic drink.
Practice 2: differences in past perfect simple and continuous
Choose the best tense (past perfect simple or continuous) to complete the following sentences. Again, remember to use contractions. And remember that simple tenses are used for states or short, finished actions when we say how many. Continuous is used for long, unfinished or repeated actions. Finally, remember that sometimes both are possible, especially when it was both a long activity (continuous), and was finished (simple).