Respuesta:
1- I was late for work because I had missed.
2- We lived in the house that my father had built.
3-We admired the picture that Lucy had painted.
4- They watered the trees that they planted.
5-The teacher corrected the tests that the pupils had written.
6- I received a good mark in my test because I had practiced.
7- The mail order house did not send me the shirt that I had ordered.
8- I had to clean the floor because my cats had knocked over the flower pots.
9-My friend was in hospital because she had slipped on a banana skin.
Explicación:
Es facil, en el past perfect usas la version de have en past. Osea had, se usa had para cualquier pronombre y luego solo pones la version past participle del verbo que usarás.