题目

High on the Qinghai-Tibet plateau lies China’s “Water tower” Sanjiangyuan.【1】The three rivers: the Yellow River, the Yangtze River and Lancang River, provide water for about half the population of China. However, human activities such as overgrazing(过度放牧) are putting this ecosystem at risk.【2】. In 2016, the Chinese government established Sanjiangyuan National Park, which was a pilot(试行) program for China’s national park system.【3】Due to the progress made in the region, Qinghai held the first National Park Forum on Aug 19.Sanjiangyuan National Park is a model of （2010•西宁）下列哪一个函数，其图象与x轴有两个交点（ ）A．B．C．D．