高考英语阅读理解专项训练（42）
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Millions of people visit Yosemite National Park every year to see the tall waterfalls and mountains. These mountains are a splendid sight when viewed form the valley floor. Lots of stores, hotels, and restaurants are needed to handle the crowds. Also, water, roads, and other service systems are part of the infrastructure (基础设施) that must be maintained.
Unfortunately, these systems are starting to break down. It’s not just in Yosemite but in national parks around the nation.