1. Parents often buy new clothes for their children on Tet. (Passive form)
-> New clothes are often bought for children by their parents on Tet
2. Miss Linh is writing the letter at the moment.
-> The letter is being written by Miss Linh at the moment
3. My sisters bought a lot of souvenirs to me last week.
-> A lot of souvenirs were bought to me by my sister last week
4. Columbus discovered America in the 15th century.
->America was discovered by columbus in the 15th century
5. They held the rice-cooking festival in the communal house.
->The rice-cooking festival was held in the communal house
6. This dress was made by a famous tailor. (Active form)
->A famous tailor made this dress
7. Nam does exercise every morning. He wants to keep fit and stay healthy.
-> Namdoes exercise every morning to keep fit and stay healthy
8. I've never talked to a more interesting person than him
-> He is the most interesting person I've ever talked to