They are digging up the football field to lay a new surface.
他们正在把足球场挖开铺一层新地面。
I-4 new surface treatment process is studied by chemical conversion coating technology.
采用化学转化膜技术，研制出I - 4表面处理新工艺。
I-4 new surface treatment process is studied by chemical conversion coating technology.
采用化学转化膜技术，研制出I - 4表面处理新工艺。
应用推荐