⇒
1. We/ used/ school/ on/ foot.
→ We used to go to school on foot.
2. about / 30km/ my town/ Ha Long Bay/.
→ It's about 30km from my town to Ha Long Bay.
3. There / many people / use / road / and / one / main reason / cause / traffic jams
→ There are many people using road and it's one of the main reason cause traffic jams.
4. How/ long / it / take/ you / Sa Pa/?
→ How long does it take you from (.....) to Sa Pa * hình như thiếu đề -_-"
5. People / use / public transports / reduce / number / private vehicles / roads
→ People should use public transports to reduce the number of private vehicles on the road.