九面体

例句：

1. 1. The cube has six faces and each face is a square.
   这个立方体有六个面，每个面都是一个正方形。
2. 2. The pyramid is a three-sided structure with a pointed top.
   金字塔是一个三边形结构，顶部是尖的。
3. 3. The tetrahedron is a four-sided shape with four equal sides.
   四面体是一个四边形形状，四条边相等。