题目

As a matter of fact, getting rid of a bad habit is ____________forming a good one. A . an effort much as B . much an effort as C . as an effort much as D . as much an effort as 答案：D园艺师傅使用如图3所示的剪刀修剪树枝时，常把树枝尽量往剪刀轴 O靠近，这样做的目的是为了（    ）  A．增大阻力臂，减小动力移动的距离  B．减小动力臂，减小动力移动的距离        C．减小阻力臂，省力 D. 增大动力臂，省力