出典:Wiktionary
Coal
出典:Wikipedia
出典:『Wikipedia』 (2011/06/12 12:02 UTC 版)
Coal is a combustible black or brownish-black sedimentary rock normally occurring in rock strata in layers or veins called coal beds or coal seams. The harder forms, such as anthracite coal, can be regarded as metamorphic rock because of later exposure to elevated temperature and pressure. Coal is composed primarily of carbon along with variable quantities of other elements, chiefly hydrogen, with smaller quantities of sulfur, oxygen and nitrogen.
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石炭層.
a piece of coal
stocked coal
a coal-pit
a coal depot
sack coal
dig coal
coal ashes
a live coal
a live coal
coal cinders
a dead coal
take in coal
a coal-factor