double-layer system 双层制

double layer-system wall 双层墙体系

double-layer control system 二元控制体系

double-layer vibration isolation system 双层隔振系统

Double-Layer Counter-Stressed Cable System 预应力双索结构

double-layer cable system 双层索

double-layer agent system 双层代理制

double-layer management system 双层经营体制

double-layer two-part system 双层二分体系