文[1]对圆锥曲线中的定点弦问题进行探讨,本文再给出与抛物线中的定点弦有关的另二个定理.定理1已知AB为抛物线C:y2=2px(p0)的一条动弦,O为坐标系原点,OA·OB=t(t为常数且t+p2≥0).(i)当A,B两点位于x轴的两侧时,AB弦过定点(p+p2+t,0).(ii)当A,B两点位于x轴的同侧时,AB弦过定点 The paper [1] discusses the fixed-point chord problem in a conic section. In this paper, two other theorems related to the fixed-point chord in the parabola are given. Theorem 1 It is known that AB is a parabola C:y2=2px(p0). Chords, O is the origin of the coordinate system, OA·OB=t (t is constant and t+p2≥0). (i) When two points A and B are on both sides of the x-axis, the AB-string passes the fixed point (p+p2) +t,0). (ii) When the two points A and B are on the same side of the x-axis, the AB string passes over the fixed point