arcuate line

例句：

1. 1. The curved roof of the building is a unique feature.
   这座建筑弯曲的屋顶是一个独特的特点。
2. 2. The concave shape of the lake reflects the surrounding mountains.
   湖泊的凹形形状反映了周围的山脉。
3. 3. The convex surface of the lens focuses light in all directions.
   透镜凸面的表面将所有方向的光聚焦在一起。