煤系
- n.coal measures; coal series
煤系煤系
coal measures
石油英语词汇(C4) ... coal measures 煤层组 Coal Measures 煤系 coal mine 煤矿 ...
coal series
a series of ... classified frequency series 分组频率级数 coal series 煤系 coarse thread series 粗螺纹系 ...
煤系