----How often do you _________ the dictionary when you are doing reading? ----Not very often. Only when I find it is necessary. A. relate to B. consult to C. refer to D. look to 答案:C17.某同学用两块长方形木板(1、2)两条松紧带(3、4)和一颗螺丝(5)制作的肌肉牵拉骨运动的模型,请看图回答:(1)图中[1]、[2]相当于两块骨,[3]、[4]相当于骨骼肌,[5]相当于关节.(2)根据图中虚线箭头判断此时[4]应处于收缩的过程,如果[5]表示肘关节则此过程表示屈肘动作(3)从这个模型来看人在运动时,要靠骨骼肌牵拉骨绕关节转动完成动作.关节在运动中起支点作用.