I. Fill in each gap with a suitable preposition.
1. I think today the boss is ... an optimistic mood.
2. They appeared surprisingly pessimistic ... their chances of winning.
3. This book contributes much ... our understanding of the subject.
4. He's very experienced ... looking after animals.
5. What exactly is the influence of television ... children.
6. The video cameras are linked ... a powerful computer.
7. Our van runs .... diesel.
8. Just keep going... a straight line; you can't miss it?
9. Can I leave these queries ... your capable hands?
10. He is receiving treatment ... shock.
11. It is possible that in the course of time a cure ... cancer will be found.
12. We should live together ... perfect harmony.