If gypsum is adopted as the face layer because the surface is smooth and flat secondarysurface-rolling procedure for surface can be omitted.
若采用石膏作面层，其光洁平整的表面可以省去表面的二次抹平工序。
2
In order to achieve Class-A surface quality for primary and secondary surfaces, the surfaces must have G3 Curvature conditions in relation to each other.
在为了达到A级表面质量的小学和中学的表面，表面必须具有的G3曲率条件，在相互关系。
3
When such damage comes to the surface of steel and rust occurs, the surface shall be cleaned by power tools to the secondarysurface preparation grade and coated as originally painting scheme.