文 [1 ]分别表述了抛物线 ,椭圆 ,双曲线的一个几何性质 ,但其表述不够完整 ,未能揭示出本质 .事实上 ,其本质 ,应是二次曲线对称轴上的两个调和共轭点的几何性质 ,因此 ,应将文 [1 ]的结论推广 ,并统一地表述为定理　设Ａ、Ｂ是非退化二次曲线Γ的一条对称轴ｌ上的两个点 (不 In [1], we describe a geometric property of parabola, ellipse, and hyperbola, respectively, but their representation is not complete enough to reveal the essence. In fact, its essence should be two harmonic conjugates on the axis of symmetry of the quadratic curve. The geometric properties of the point, therefore, the conclusion of [1] should be generalized and expressed collectively as the theorem that A and B are two points on a symmetric axis l of a non-degenerate quadratic curve (