Here are the complete sentences using "will" or "won't" based on the suggested words:

1. Their team **will be** champions.
2. People **will use** less private vehicles in the future.
3. Who **will make** the last decision?
4. The countryside **will disappear** in the future because of urbanization.
5. What **will they do** to reduce traffic jams?
6. **Will it rain** tomorrow?
7. She **won't want** to see him.
8. **Will it be** possible for people to live on the Moon in the future?