身____其____    应____不____    赞____不____    千____一____

无____不____    各____己____    香____可____    肃____起____

已知全集$U=\{2,3,5\}$，A是U的子集，且$A=\{\left|a-5\right|,2\}$,$C_{U}A=\left\{5\right\}$，则a的值为（  ）

某同学分别测量了三块橡皮泥的质量和体积，并根据测量数据画出如图所示的图像，橡皮泥的密度是____ g／cm³。若另一块同种橡皮泥的体积为20 cm³，其质量是____ g。

根据材料内容，选择正确答案。

    Tom went to see his grandparent with his father. In the train Tom often put his head out of the window. His father said, "Tom, don't put your head out of the window." But Tom went on putting his head out of the window.

    His father took Tom's hat quietly and hid it behind his back and said to Tom, "You see your hat is gone." Tom was afraid. His father said, "Well, whistle(吹口哨) once. Maybe your hat will come back." Tom whistled. His lather put his hat on Tom's head quickly. "Oh! It's wonderful!" Tom laughed and said. He quickly took his father's hat and threw it out of the window. "Now it's your turn to whistle, Dad!" he said happily.

已知点A（1，1），B（3，3），则线段AB的垂直平分线的方程是（　　）