II/
1. was going
2. had ever watched
3. has become
4. will have finished
III/
1. destruction
2. environmental
3. productive
4. naturally
IV/
1. Our car is going to be repaired by these mechanics this afternoon.
2. If I were a good swimmer, I could have won the race last week.
3. Studying abroad is considered to be a wonderful opportunity for students.
4. If I had known you were asleep, I wouldn't have made so much noise when I came in.
5. Kelvin has four cats, two of which are black.
6. The air hostess was the only person to survive in the crash.
