伪顶 wěidǐng false roof Definitions Defs Origin Strokes Stroke Words Sentences Sents 伪顶 偽頂 wěidǐng false roof a thin layer of rock in a coal mine that sits immediately above the coal seam and collapses easily when the coal is removed
伪顶 偽頂 wěidǐng false roof a thin layer of rock in a coal mine that sits immediately above the coal seam and collapses easily when the coal is removed
