“成曲线”可以翻译为 “form a curve” 或 “be in the shape of a curve” ，具体使用哪个表达可根据语境来决定。例如：
* The path forms a curve as it winds through the forest.（这条小路蜿蜒穿过森林，形成了一条曲线。）
* The edge of the lake is in the shape of a curve.（湖的边缘呈曲线形状。）