Cause Analysis and Repair Measures for Deformation Failure in Air Return Way of No.21 Mining Block in Liangbei Mine是什么意思_Cause Analysis and Repair Measures for Deformation Failure in Air Return Way of No.21 Mining Block in Liangbei Mine在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句