题目内容：

Natural sites and historic buildings, when left alone, can slowly be in bad condition. 1.For these reasons we must protect them.

“World Heritage" is the title given to places chosen from natural sites and buildings around the world. These places are considered special, valuable and require protection. They may be places of nature or cultural heritages that are the pride of the people in the country. 2. Each is a treasure of our planet that must be protected for us and our future generations.

Even extremely beautiful natural environments can be in bad condition if they are left alone. 3.For instance, the Galapagos Islands are now protected by rules that stop people from bringing or removing plants and animals to or from the islands, moving rocks and touching the animals. In the US, people are not allowed to visit Grand Canyon National Park by vehicle. It aims to protect the park's environment from the gas produced by cars. 4. Australia is making stricter laws to prevent agricultural chemicals from flowing into the ocean near the Great Barrier Reef. Efforts are also being made to protect Natural Heritage sites in Japan. In Shiretoko, only a small number of people are allowed to walk on its nature path at the same time. 5.

A. They may also be home to endangered species(物种).

B. Today there are 183 Natural Heritage sites around the world.

C. People can change these places too, just as the wind and rain can.

D. Natural Heritage is valued for geographical characteristics and beautiful scenery.

E. That's why measures are being taken around the world to protect them.

F. It can reduce the risk of people accidentally stepping on valuable plants.

G. There are even security guards there who can arrest people that break the rules.