题干
Alice was very sorry to hear that her grandmother had _____ two days before.
A：broken off
B：passed off
C：given away
D：passed away
答案(点此获取答案解析）
D
A：broken off
B：passed off
C：given away
D：passed away
的光滑斜面上，由底端向顶端做匀加速运动。当物体运动到斜面中点时，去掉推力，物体刚好能到达顶点，则推力的大小为（ ）