概括：内容选自老托福听力，是练习托福听力的绝佳材料。
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Yellowstone National Park
National Park Service
Ulysses S. Grant


我就是想赞美下身边那瓢泼的景色和为绿化做贡献~
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 1800s. 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 19th 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 trained staff members. The park service also protects the animals and plants within the parks.