Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions from 28 to 31.

In 1959, the government of Egypt was working on a plan to build a dam on the River Nile. It was called the Aswan Dam, and it was intended to generate electricity and allow the river water to be used for agriculture. There was one big problem with the plan, though. The dam would flood a nearby valley that contained ancient Egyptian treasures, including two enormous stone temples.

It can be difficult for governments to choose culture and history over economics. However, if countries always made decisions like this, the majority of the world's ancient sites would end up being destroyed. Luckily, UNESCO stepped in. They formed a committee that tried to convince Egypt to protect its ancient treasures. With support from many countries, they were finally successful. The huge temples were carefully removed from their original site and moved to a safe location so that the dam could be built.

After their success in saving the temples in Egypt, UNESCO went on to save more sites around the world. They protected lagoons in Venice, ruins in Pakistan, and temples in Indonesia. With industrialisation changing the world rapidly, there were many sites that needed to be saved. Eventually, UNESCO formed the World Heritage Organization to protect important natural and historic sites wherever it was necessary.

By now, the World Heritage Organization has protected hundreds of sites ranging from beautiful natural islands to buildings in large cities and ancient ruins. If you're able to visit any of the many protected sites, you'll agree it was worth it.

Mary didn't do her homework last Monday, _____? A. did Mary