Sure! Here are the sentences based on the clues provided:

2. The longer he spends practicing the piano, the more proficient he becomes.

3. Some tourists took photos of the sunset when they noticed a wild bear.

4. The children were excited because they had never explored the seabed before.

5. I wish I had done more community service before my graduation.

6. Katie may win the competition unless she goes to practice sessions regularly.

7. Have you ever come to school late or failed an important exam?

8. It is essential to put a barrier around the campsite to keep wild animals away.

9. Christian joined a 2-week course at the army camp in Kentucky last summer.

10. She has already seen the gong show, but she hasn't seen the tribal dance show yet.