①表明中国政府尊重公民权利，保障基本人权

②标志着我国人权事业发展进入一个新的阶段

③扩大了我国民主主体和权利主体的范围

④有助于使公民真正认识到自己是国家的主人

如图所示是一透明的圆柱体的横截面，半径R=2cm，折射率n= $\sqrt{3}$ ．真空中一束光线沿平行于直径AB的方向从D点射入透明体，折射光线恰好通过B点．真空中光速c=3.0×10⁸m/s，求：

①光在透明体中的传播速度v．

②入射点D与AB间的距离d．

如图所示，静止在水平桌面上的木块，在水平方向受到推力F_１、F_２和摩擦力。已知　F_１＝10N，F_２＝2N，若撤去F_１，木块在水平方向上受到的合力为（    ）

A

    Yao Ming is a very good basketball player in the world. He is 25 years old. He was born in Shanghai, but he lives in the USA with his parents now. Yao Ming is quite tall. But he isn't so strong. He was in the Rockets Team after he left (离开)China. He plays very well in the NBA. Many people come to his match(比赛) in America. Lots of Chinese young men watch the matches on TV. Yao Ming wants to be a superstar one day.