To Compare Effects of Two Method on Coal Quality and Economic Results between the Fully-mechanized Mining with Roof Caving and the method of One-time Cutting Whole Height是什麼意思_To Compare Effects of Two Method on Coal Quality and Economic Results between the Fully-mechanized Mining with Roof Caving and the method of One-time Cutting Whole Height在線翻譯_英語_讀音_用法_例句