plain face

• 平面

plain face的用法和样例：

例句

1. Flat or spherical measuring face.
   测头为平面还是球面。
2. As the ancient plain uplifted, it formed the mountain erosion surface with the potholes on its surface.
   准平原及壶穴最后被抬升到山地的顶部，构成了山地夷平面。