concave rim

例句：

1. 1. The car's concave rim is designed to protect the driver from wind and rain.
   这辆车的凹面边缘设计用来保护司机免受风和雨的侵扰。
2. 2.The artist used a concave rim to create a three-dimensional effect on the painting.
   艺术家使用凹面边缘在这幅画上创造了一种三维效果。
3. 3.The concave rim of the bowl is perfect for holding small items like coins or keys.
   碗的凹面边缘非常适合放置硬币或钥匙等小物品。