... ballast concrete 石碴混凝土 ballast pit采石场 ballast rod 冲唤钻杆 ...
例句
例句
The practice indicated that evident benefits were obtainedwhen the forestry cableway was applied to the stone pit operations in specially difficult topographies. 实践表明在特殊困难地形将林业索道用于采石场作业有明显效益。