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!

线段有两个端点。

下图中读数操作错误的是____，这样会导致结果____；该铅笔的测量结果是：____。

汇汇对同桌文文说：“上中学以后，我越来越不愿意什么事都告诉父母了，有什么事情我愿意自己做决定。”文文说：“我也是这样。”这两位同学的对话，反映青少年心理发展的特点是（  ）

如图，网格中每个小正方形的边长均为1，线段AB，线段CD的端点均在小正方形的顶点上．