unfaced surface

例句：

1. 1.The unfaced surface of the rock is smooth and shiny.
   岩石的未被覆盖表面光滑且有光泽。
2. 2. The scientist discovered an unfaced surface on the moon.
   科学家在月球上发现了一个未被覆盖的表面。
3. 3. The engineer carefully unfaced the surface of the machine before starting work.
   工程师在开始工作前仔细地处理了机器的表面。