angle rib

例句：

1. 1.The angle of the roof is perfect for ventilation.
   屋顶的角度完美，有利于通风。
2. 2.The angle of the table is too sharp for comfort.
   桌子的角度太尖锐，不舒服。
3. 3. The angle of the roof has been modified to improve energy efficiency.
   屋顶的角度已经修改过，以提高效率。