【答案解析】China's Tibet Autonomous Region is situated on the main body of the Qinghai-Tibet Plateau. With high altitude, unique geographical features and rich wildlife, water and mineral resources, it has been called the "Roof of the World" and the "Third Pole of the Earth." It is not only the "source of rivers" and the "ecological source" for the areas in South and Southeast Asia, but is also the "starter" and "regulating area" of the climate of China and indeed of the Eastern Hemisphere as a whole. // The Tibet Autonomous Region is 1.22 million sq km in area, with an average altitude of well over 4,000m. above sea level. It boasts a unique natural ecology and geographical environment. The climate in Tibet turns gradually from being warm and moist to cold and dry from its southeast toward its northwest. Ecologically, the changes are manifested in belts from forest, bush, meadow and steppe to desert. The complex and varied terrains and landforms as well as the unique type of ecological system have created a natural paradise for biodiversity. // The Chinese government attaches great importance to ecological improvement and environmental protection in Tibet. It has made tremendous efforts to strengthen ecological improvement and environmental protection work in Tibet, promote the sustainable development of its economy and society, and improve the quality of life of the people of its various ethnic groups. // For over half a century, ecological improvement and environmental protection in Tibet, as an important part of the effort to modernize Tibet, has, together with economic development, social progress and enhancement of people's riving standards, pressed forward and made great achievements. // It would help clarify some people's misunderstanding concerning Tibet's eco-environmental problem and enhance their understanding of Tibet to review the progress of the ecological improvement and environmental protection work in Tibet, to present the status quo of this undertaking, and to envisage the prospects of sustainable development for the region. // (Excerpts from the English version of the White Paper "Ecological Improvement and Environmental Protection in Tibet" issued by the Information Office of the State Council of PRC in March 2003)