从1999年6月19日江泽民同志在西安向全国发出实施西部大开发战略的号召开始，西部开发已经进行了10年了，在这期间，西部经济增加明显快于全国水平，人民的生活得到显著改善．但是也出现了一系列的生态环境问题，如草原退化，土地沙化，森林减少等．已经引起了相关部门的重视．

下列哪一项不是我国西部开发中存在的主要问题（　　）

根据短文理解，从A、B、C、D四个选项中选择最佳答案填空。

    Jimmy started painting when he was four years old. When he was six, he was already very good at it. He 1 many beautiful and interesting pictures, and people 2 a lot of money for them. They said, “This boy's going to be 3when he's a little older, and then we're going to 4  these pictures for a lot more money. Then we will get rich.”    

    Jimmy's pictures were 5 from other people's because he never painted on the whole piece of  6. He painted on half of it, and the other half was always 7.

  “That's very clever,” everyone said. “8 else does that!”

    One day somebody bought one of Jimmy's 9 and then said to him, “Please tell me this, Jimmy. Why do you paint on the 10half of your paper, but not on the top half?”

  “Because I'm small,” Jimmy said, “and my brushes don't reach very high.”