It was Sunday yesterday. The weather was fine. It was sunny and there were no clouds in the sky. Sandy and Sue got up early in the morning. Now they were in the park. It is a big park and it's so beautiful. They saw many people there. Some boys played football on the grass. Some girls danced under the tree. An old man walked beside the lake. A young woman and her little son looked at the fish in the lake. How happy they are!

随着智能手机和网络的普及，截至2017年1月，我国手机网购用户规模达4.8亿户，同比增长43.9%，手机网购的使用比例由64.8%提升至82.3%。全国开展在线销售的企业比例为47.6%，制造业、批发和零售业的比例相对较高，分别达到52.4%和54.9%。

结合材料，运用“生产与消费的关系”的有关知识，分析智能手机和网络的普及以及网络消费可能产生的积极影响。

材料一：中国早期民族企业

材料二：民国初年历年新注册工厂数量一览表（不包括矿山，单位：家）

如图所示，在光滑的水平面上放置一个质量为2m的木板B，B的左端放置一个质量为m的物块A，已知A、B之间的动摩擦因数为μ，现有质量为m的小球以水平速度v₀飞来与A物块碰撞后立即粘住，在整个运动过程中物块A始终未滑离木板B，且物块A可视为质点，求

当光线从水中射向空气时，它的反射光线如图所示，请画出入射光线和折射光线．

​