(man) Welcome to Yellowstone National Park. Before we begin our nature walk today, I'd like to give you a short history of our National Park Service. The National Park Service began in the late 1800's. A small group of explorers had just completed a month-long exploration of the region that is now Yellowstone. They gathered around a campfire, and after hours of discussion, they decided that they should not claim this land for themselves. They felt it should be accessible to everyone.
So they began a campaign to preserve this land for everyone's enjoyment. Two years later, in the late nineteenth century, an act of Congress signed by President Ulysses S. Grant proclaimed the Yellowstone region a public park. It was the first national park in the world. After Yellowstone became a public park, many other areas of great scenic importance were set aside and in 1916 the National Park Service was established to manage these parks.
As a park ranger, I am an employee of the National Park Service. In a national park, park rangers are on duty at all times to answer questions and help visitors in any difficulty. Nature walks, guided tours, and campfire talks are offered by specially training staff members. The park service also protects the animals and plants within the parks.内容来自 听力课堂网：http://www.tingclass.net/show-8562-245578-1.html