短语词组短语bowstring g truss 弓弦桁架bowstring roof truss 弓弦屋架;拱形屋架;弓弦式屋架double bowstring truss 双弓弦桁架;鱼形桁架laminated bowstring truss 叠层弓弦桁架truncated bowstring truss 平端弓形桁架;平截端弓形桁架ribbon grenext tod bowstring truss 弓弦桁架 返回 bowstring truss