题目

一物体在二力作用下静止，若使其中一力逐渐减小到零，再逐渐恢复到原值，而且力大小变化时方向不改变,则物体的运动是 A.一直加速                                                     B.一直减速C.先加速后减速                                               D.先减速后加速 I really don’t understand how he can ______away with cheating. A．make B．run C．steal D．get