I did something wrong today.

    While at the beach this afternoon. I met a boy called Bob We talked a lot. He said that it was fun playing on the cliffs (悬崖). I told him that I was not allowed to go near that place(Mum and Dad had always told me it was dangerous to play there). He called me a coward. I wanted to prove to him that I was just as brave, so I agreed to go with him.

    We wanted to make our way down to explore (探索)the area, so Bob started to climb down and I followed him. Unluckily, some rocks came down after us. One of them nearly hit my head. We could not get back up. We shouted and shouted for help, but for a long time no help came. I was really scared. I wanted to cry. Then, we heard some sounds. Someone had heard us. A woman tied (系 )a rope around herself while a man at the cliff top held the rope. She made her way down to save us.

    My parents were relieved (宽慰的)that I was unhurt, but they were angry that I had done such a risky thing. I apologized and promised that I would not do anything like that again.

将圆 $\{\begin{array}{l}\hfill \\ \hfill \end{array}\begin{array}{c}x=2cos\theta ,\\ y=2sin\theta \end{array}$ （ $\theta$ 为参数）上的每一个点的横坐标保持不变，纵坐标变为原来的 $\frac{1}{2}$ ，得到曲线 $C$ ．

图所示，甲、乙两个体积相等的小球分别放在两个装有不同液体的容器中处于静止状态，此时容器中液体深度不同，但液体对容器底部的压强相同，则    （  ）