圆锥投影

例句：

1. 1. The cone is the top of a cone-shaped object.
   圆锥是锥形物体的顶部。
2. 2. The cone was used to measure the height of trees.
   圆锥被用来测量树木的高度。
3. 3. The cone is made of hard stone.
   圆锥是由坚硬的石头制成的。