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.
他们是最为贫困的穷人和岛国居民：分布在100国家的10亿人口。
They are the poorest of the poor and those living in island states: 1 billion people in 100 countries.
作为美国城市中，未对居民聚居地点及分布作出区域规划的最大都市，休斯顿城也因此闻名。
The Houston metropolitan area is also noteworthy as being the largest in the United States without formal zoning restrictions on where and how people can build.
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