单选题
1分
When a point rotates about an axis and at the same time, moves parallel to that axis, it describes (...
When a point rotates about an axis and at the same time, moves parallel to that axis, it describes ( ).
参考答案: C
参考解析: 注:如果某一点绕轴旋转,同时沿该轴平行线移动,则产生螺旋线。