1. Ho CHi MInh City with the population of over 8 million is bigger than any other cities in Viet Nam.

Ho Chi Minh city is the biggest city in Viet Nam with the population of over 8 millions.

2. Angel Falls is over 1,000 feet higher than any other falls in the world.

Angel Falls is the highest fall in the world (with 1,000 feet higher than any other falls in the world).

3. Lake Superior in North America is a freshwater lake; it is larger than any other freshwater lakes in the world.

Lake Superior in North Anerica is the largest freshwater lake in the world.

4. Remember to bring the compass; if not we will get lost in the forest.

You must bring the compass or we will get lost in the forest.

5. Take a waterproof coat dueing your trip to Fansipan MounTain because it is rainy there.

You should take a waterproof coat during your trip to Fansipan MounTain because it is rainy there.

6. It is very important that you arrive on time at school.

You must/should arrive on time at school.

7. It is very dangerous to walk alone after 10pm in that park.

You musn't / shouldn't walk alone after 10pm in that park.

8. Taking a boat trip around the islands in Ha Long Bay is the most important thing of the trip.

You need to take a boat trip around the islands in Ha Long Bay, it is the most important thing of the trip.

9. Antarctica is older than any orher place in the world.

Antarctica is the oldest place in the world.

10. It is wrong of us to write on the walls or tables in our classroom.

We shouldn't have written / shouldn't write on the walls or tables in our classroom.