=>
16. didn't come
IV/
1. can -> could
2. separate -> separated
3. worked -> has worked
4. than -> to
5. have to -> has to
V/
1. We wish Nam helped us.
2. She wishes she had free time to go camping.
3. I was advised to take part in the course by Tam.
4. My father has given up smoking since last year.
5. They started working in that factory in 2001.
VI/
1. His exercisees has already been finished.
2. Rice was planted in those fields.
3. A car and a truck can  be driven by Nam.
4. He hasn't been known well.
5. Our pen pals will be met at the station.
16. Jean cloth was made completely from cotton in the 18th century.

17. The Ao dai has been mentioned in their songs by a lot of musicians for centuries.

VII/
1. Yes, they did.
2. Because it is traditional, fashionable and also modern anyway.
3. My favorite clothing is Ao dai.

VIII/
1. It is divided into two regions, known as West Malaysia and East Malaysia.
2. Yes, it is.
3. Bahasa Malaysia, english, chinese and tamil.