Ответ:

1. This letter has recently been brought by the secretary

2. The flat will have been being decorated for two months by the end of may.

3. The work would be finished by the time I came

4. these houses have been built this summer

5. All the necessary things had been packed by 6 o'clock

6. After our exams have been passed we will have our vacations

7. Before I called on him the film had been being watched for an hour by Alec

8. A lot of time has been spent on this work

9. In this house has been being lived for 2 years by the end of the year

10. When i entered the room I saw that the vase had been broken

11. The document hasn't been found yet.