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环境保护问题已成为全人类最关注的问题之一.以环境保护为主要内容的应用题即环保型应用题,愈来愈多地出现在各种级别的试题中.下面几例环保型应用题中的数据均来自《人与自然》杂志和《光明日报》. 例1 水土流失是我国西部大开发中最突出的生态环境问题,全国9100万亩25度以上的坡耕地需要退耕还林,其中西部地区占70％.2000年国家确定在西部地区退耕土地面积为515万亩,以后每年退耕土地面积递增12％. (1)试问从2000年起,到哪一年西部地区基本解决退耕还林问题?
The issue of environmental protection has become one of the most concerned issues for all human beings. The application topics that focus on environmental protection, that is, environmental protection applications, are increasingly appearing in various levels of test questions. The following examples of environmental protection applications The data in both are from “Man and Nature” magazine and “Guangming Daily”. Example 1 Water and soil erosion is the most prominent ecological environment problem in the development of western China. 91 million mu of sloping farmland above 25 degrees need to be converted back to farmland. The western region accounts for 70%. In 2000, the country determined that 5.51 million mu of land was to be reclaimed from the western region, and that the area of land to be reclaimed should increase by 12% each year. (1) From the year 2000, the year to which the western region basically resolved to return farmland to forestland problem?