Respuesta:
1)_ He had learned this recipe by heart
2)_ We had become friends over the year.
3)_ They had been here before.
4)_ I had not learned a single thing in this class.
5)_ He had never seen a bear before she moved to Alaska.
6)_ They had studied English.
7)_ The children had not done the homework.
8)_ Paul had worked as an engineer.
9)_ I had saved my document before the computer died.
10)_ Ronnie and Stefanie had not met before the party
