Sure! Here are the completed sentences based on the prompts given:

1. What do teenagers fond of?
2. Tourists are keen to see the terraced fields.
3. I do DIY in my freetime.
4. She’s crazy to upload pictures on Facebook.
5. How many ethnic groups are there in Vietnam?
6. Women play an important role in Thai family life.
7. She uploads her pictures to Facebook.
8. If you cook dinner, I will make cake.
9. If it doesn't rain, they will go camping.
10. You stay healthy if you eat a banana every day.
11. You will pass the final exam if you study hard.
12. There won’t be any interesting activity during Tet here.
13. They will watch the New Year’s Eve Ball drop in Times Square.
14. Vietnam gives lucky money to old people and children.
15. Linh loves to listen to pop music.

Feel free to ask for any more help!