Here are the suggested answers for the fill-in-the-blank questions based on the provided text:

1. **B. in**
The Thai live **in** farming on their burnt-over land and wet-rice terraced fields.

2. **A. in**
The Thai live **in** terraced fields.

3. **C. communal**
The house is a place where villagers gather for festivals and rituals.

4. **A. but**
There were lots of interesting folk games, **but** Kenny stayed a little longer to join them.

5. **A. What**
'What colour is ____ dress in red and black costume?' 'The Dao'

6. **B. an**
What colour is **an** symbol of good luck for the Hoa?

7. **B. Rice cultivation**
The main economic activity of ethnic people in Sapa is **Rice cultivation**.

8. **A. The**
The ethnic Khmer live in **the** Mekong Delta of Vietnam.

9. **D. has designed**
The Vietnam Museum of Ethnology **has designed** by the architect Ha Duc Linh, a member of the Tay ethnic group.

10. **B. Really?**
'I have just taken an elephant ride in Buon Don.' 'Really? How interesting!'

Feel free to adjust any of the responses based on the specific context or instructor preferences!