题目

如图所示，要把残破的轮片复制完整，已知弧上的三点A，B，C． 用尺规作图法找出所在圆的圆心；（保留作图痕迹，不写作法） 答案：【解答】解：分别作AB和AC的垂直平分线，设交点为O，则O为所求圆的圆心；They suggested that the professor           just now          chairman of the meeting. [     ] A.referring to;was madeB.referring to;be made C.referred to;be madeD.referred to;was made