题目

(2009天津河东模拟)---Your sister nearly _______ all her spare time to her study during the three years. ----That's right， or she ________ the first place in her school in the College Entrance Examination. A. devoted; wouldn't have taken                 B. spent; wouldn't have taken C. had devoted; hadn't taken                          D. had spent; couldn't take（2013·天津八中高三第三次月考，18题）如图所示，小球A系在细线的一端，线的另一端固定在O点，O点到水平面的距离为h。物块B质量是小球的5倍，至于粗糙的水平面上且位于O点正下方，物块与水平面间的动摩擦因数为μ。现拉动小球使线水平伸直，小球由静止开始释放，运动到最低点时与物块发生正碰（碰撞时间极短），反弹后上升至最高点时到水平面的距离为h/16。小球与物块均视为质点，不计空气阻力，重力加速度为g，求物块在水平面上滑行的时间t。