convex-concave

例句：

1. 1. The surface of the car is convex.
   汽车的表面是凸的。
2. 2. The shape of the bowl is concave.
   碗的形状是凹的。
3. 3. The geometry of the design is a combination of both convex and concave shapes.
   这个设计的几何形状是凸形和凹形的结合。