Sure! Here are the completed sentences:

6. I like making models in my free time.
→ I am **fond of making models in my free time.**

7. We all find painting interesting because it’s a creative activity.
→ We all think **that painting is interesting because it’s a creative activity.**

8. It isn’t necessary to finish the work today.
→ You don’t **have to finish the work today.**

9. My sister loves chatting with her friends in her free time.
→ My sister enjoys **chatting with her friends in her free time.**

10. It took me three hours to make this pottery jug.
→ I spent **three hours making this pottery jug.**