一质点沿 轴运动,其加速度 与位置坐标 的关系为 。如果质点在原点处的速度为零,试求其在任意位置处的速度

sedThe best wy to prevent their polluting _____ , but the sky is still not cler.is used B．re used C．hs been used D．hve been usedA．is usedB．are usedC．has been useD．have been used