Помогите пожалуйста нужно слова которые в скобках поменять в Past Perfect(had/hadn039;t)

1 bought, had seen
2 learned, had watched
3 phoned, had found
4 visited, had read
5 had collected
6 arrived, had changed
7 met, had become

Подсказка: то событие, которое произошло ранее - в Past Perfect. А то, которое после него либо просто позже - в Past Indefinite.