surface roughness

例句：

1. 1. The surface of the metal is very smooth and does not have any roughness.
   金属的表面非常光滑，没有任何粗糙。
2. 2. The engineer measured the surface roughness of the machine before it was used.
   工程师在机器使用前测量了其表面粗糙度。
3. 3. The surface roughness of the material affects its ability to bond with other materials.
   材料的表面粗糙度影响其与其他材料的粘合能力。