1) turned
2) had turned
3) finished
4) had finished
5)he thought that he had losted the money
6) Ann told me that she had seen an interesting film
7) when I came home, mother already had ccoked dinner
8) when father returned from work, we had already done our homework
9) when the teacher entered the classroom, the pupils had already opened their books
10) Kate gave me the book which she had bought the day before
11) nick showed the teacher the picture which he had drawn
12) the boy gave the goats the grass which he had brought from the field
13) mother saw that Nick hadn't washed his hands