III
1. If you didn't live so far away, we would visit you very often
2. If I had had money on me, I would have gotten a taxi
3. Unless you work harder, you won't pass the exam
4. The thief admitted to the detective that he had stolen Mr Smith's car
5. Having collected enough information, the group started writting the report

IV
1. A ( to practise -> practising )
2. C ( to cycle -> cycling )
3. B ( did he have to -> he had to )
4. C ( to talk -> talking )
5. D ( to read -> read )

V
1. B
2. B
3. A
4. C
5. D
6. B
7. B
8. C
9. B
10. A

V
11. B
12. D
13. A
14. D
15. A
16. B
17. B
18. B