=>
I/
1. was rescued
2. had taken/rang
3. didn't enjoy/hadn't rained/would have been
4. to work
5. buying
6. is supposed
7. repaired
8. worked
9. has collected
10. enter/accompanied
II/
1. had seen
2. saw/ had lefft
3. will have forgotten/come
4. went/don't/will miss
5. were coming/ran
6. asking/to raise/to do
7. arrive/will be probably raining
8. are you laughing/Has Roger been telling
9. using/to borrow/typing
10. are being destroyed
III/
1. Plans for an extension to the house have been drawn by the architect.
2. Jenny used to play tennis better than now.
3. I never have intention of going to the meeting.
4. The English owe the introduction of potatoes and tobacco to Sir Water Raleigh.
5. We saw the housein Stratford-on-Avon where Shakespeare was born.
6. The door was too heavy for the child to push it open.
7. Andrew suggested going for a walk in the park./Andrew suggested we should go for a walk in the past.
8. The union delegate observed that he would be very surprised if his members agreed to that.
9. You don't have to finish by Saturday.
10. You'd better apologise to Sally.
11. He broke the world record on his second attempt.
12. Despite my strong disapproval of your behavior, I will help you this time.
13. Be careful or else you will have a fall.
14. I'm sorry not to have attended Professor Baker's lecture.
15. The meat was so rotten that it had to be thrown away.
16. The car belongs to Mrs. Edward.
17. He couldn't possibly have known that his brother was seriously ill.
18. The concert may have to be cancelled.
19. Professor Van must be met at the airport.
20. According to the station clock, it was half past ten.