A) Do the QUIZ
B) PRACTICE ONLINE:
1. https://www.englisch-hilfen.de/en/exercises/tenses/past_perfect.htm
2. http://www.adelescorner.org/grammar/past_perfect/past_perfect_neg.html
Choose between the preterit and the past perfect
3. https://www.englisch-hilfen.de/en/exercises/tenses/past_perfect_simple_past.htm
4. https://www.english-grammar.at/online_exercises/tenses/t079-past-past-perfect.htm
5. http://www.adelescorner.org/grammar/past_perfect/past_perfect_vs_past_simple.html