bollards是什么意思

用法例句

In this paper, the studs constituted of tubes and clips are talked aboutThe new type of light gauge steel system studs are divided into 2 parts: the single-piece studs and the sq.

目前,我国轻钢龙骨体系柱的组成型式主要有H型钢、C形钢和方钢管等几种。