Part D:
I. 1. d. will
2. c. dirty
3. c. safe
4. d. made
II. 1. No, there aren't.
2. Two separate teams.
3. Because they want to get the best score.
4. Yes.
Part E:
III. 1. Because I had a bad cold, I didn't go to school yesterday.
2. Although Lan can sing very well, she can't play the piano.
3. If we use the car all the time, we'll make the air dirty.
4. Tea is the most popular drink in London.
Part C:
1. A. reduce
2. B. hasn't left
3. C. most peaceful
4. D. Although
5. A. visited
6. A. is / will go
7. C. telling
8. D. clothes
