题目

读下图完成下列各题。【1】上图是我国北方某地区图，图中阴影区（ ）A. 地处我国地势的第三级阶梯上B. 水土流失是当地主要的生态环境问题C. 人口稠密需要扩大耕地面积，增加粮食产量D. 应大力发展采矿业，增加农民收入【2】与长江比，对图示河流水文特征表述正确的是（ ）A. 结冰期较短 B. 水能丰富 C. 含沙量较少 D. 汛期较短—According to a recent survey, many students have poor eyesight (视力).—In my opinion, reading on mobile phones too often is the ________ of having poor eyesight.A.costB.resultC.cause