圆锥曲线是高考的重点和热点,也是学生学习的一个难点,高考考题常考常新,一般是高考中的压轴大戏,命题者可谓是费尽心机,但出题中有偶然也有必然.笔者在做2007年重庆卷文科21题后,受抛物线有关知识的启发,通过变形、猜测、论证,发现了抛物线中与焦点弦有关的两个性质,并把它推广到椭圆和双曲线中,行之成文,与同行交流.性质如图, Conic curve is the focus of the college entrance examination and hot spots, but also a difficult student learning, college entrance examination exam often test new, usually the finale of the college entrance examination drama, proposition can be described as exhausting effort, but the questions are occasional and inevitable. Inspired by the knowledge of parabola, after making 21 subjects in 2007 in Chongqing, we found two properties of the parabola related to the focus chord and extended it to ellipse and hyperbola Written, communicate with peers. The nature of Figure,