Ответ:
1. Nick showed the teacher the picture which he had drawn.
2. The boy gave the girl the flowers which he had brought from the field.
3. Mother saw that Nick hadn't washed his hands.
4. I didn't know that my friend hadn't come yet.
5. When I woke up yesterday, parents already had gone to work.
6. The children thought that his father hadn't come home yet.
7. Mary told us that she had cooked a good dinner.
8. Yesterday I found the book which I had lost in summer.
9. When we came to the station, the train had already left.
10. I had finished my test by the lesson was over.
Объяснение: