deep down in the earth for thousands of years, the dead forest has rotted away and bee coal．
A. Having buried
B. Being buried
C. Buried
D. To be buried
网友回答
A. Having buried
B. Being buried
(答案→)C. Buried
D. To be buried
解析：句意：被埋在了泥土中数万年，死亡的森林已经腐烂变成了煤。动作bury与其逻辑主语the dead forest是被动关系，故用过去分词作原因状语，选C。