Here are the correct forms of the words in brackets:

1. Nick is into **discovering** (discover) the life of ethnic people in Vietnam.
2. Some ethnic peoples in the **mountains** (mountain) remain still (keep) their traditional way of farming.
3. Which do you think is more **colorful** (color) – the Tay's or the Nung's costumes?
4. Buffalo-drawn carts can be **seen** (see) in the countryside during harvest time.
5. I just (check) the **notifications** (notification) and it seems we won one more prize.
6. Their family lived more **happily** (happy) after they moved to the countryside.