I,
3/ => You must arrive on time.
4/ => No beach in Vietnam is longer than Tra Co Beach.
5/ => Ha Noi is often warmer than Lang Son in summer.

II
Great Barrier Reef is the largest coral reef in the world. It is close to coastal Queensland of Australia. Its length is 2600 kilometers. It makes up nearly 3000 coral reefs and over 6000 island. It is listed in UNESCO World Heritage Site. Great Barrier Reef is the largest structure makes living things. It can see from outer space.