pencil of quadric hypersurfaces

例句：

1. 1. The quadric equation is a mathematical model that describes the shape of an object.
   四元二次方程是描述物体形状的数学模型。
2. 2. The quadric hypersurface is a type of surface that has four distinct points of intersection.
   四元二次超曲面是一种具有四个不同交点的曲面类型。
3. 3. In geometry, a quadric hypersurface is a surface with four distinct points of intersection.
   在几何学中，四元二次超曲面是一个具有四个不同交点的曲面。