毕竟煤炭矿床本身就是石化的泥炭沼泽，而泥炭的成份是腐烂的植物。当粘土泥浆逐渐硬化成页岩石，腐烂的植物则在上面留下了它们的印记。

Coal deposits, after all, are petrified peat swamps, and peat is made from decaying plants, which leave their imprints in mud and clay as it hardens into shale stone.

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其为在水泥硬化体上被覆有合成树脂水性分散体、膨润性粘土矿物及以颜料为主成分的物质隔绝剂所成的水泥复合体。

In the cement composite, a hardened cement product is coated with a substance block agent composed chiefly of an aqueous dispersion of synthetic resin, a swelling clay mineral and a pigment.

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