美国的国家公园就是分布于世界各地类似的系统中的典范，其理念就是在保护区内人类只是游客，而不能成为永久居民。
America's system of national parks, a model for similar set-ups around the world, was based on the idea of limiting human presence to passing visits, rather than permanent habitation.
在美国怀俄明州黄石国家公园里，一只勇敢的野鼠与一头身量一百倍的郊狼对峙。
A courageous vole takes on a coyote a hundred times his size in Yellowstone National Park, Wyoming.
现在在美国西部的一些地方有一些非常有趣的洞穴，尤其是在国家公园里。
Now there are some pretty interesting caves in parts of the western United States, especially in national parks.
应用推荐