| 例句 |
It drives a hole into the coal seam using a hydraulic bit.它用水力钻头在煤层上钻洞。A red bed of coals blazed with molten fury.火红的煤层熊熊燃烧着。The average U.K. coal seam is one metre thick.英国煤层的平均厚度为一米。There are substantial reserves of methane gas trapped in coal seams in the area.该地区煤层之中储有大量的甲烷气体。 |