1. We have seen the doctor there.
2. Mary will have put the salad on the plates by 6 o'clock.
3. Nick had brought some water when we came into the house.
4. They have just eaten all the cakes.
5. He has brought a box of chocolates for her.
6. The window had been opened by someone when we entered the room.
7. Pupil-on-duty will have cleaned the blackboard by the end of the lesson.
8. My sister has already cleaned the floor.
9. Mother has just opened the door.
10. We have bought this tape-recorder recently.