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煤中微量元素的研究意义重大和广泛。
The research of trace elements in coal has great of significance.
youdao
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煤中微量元素是世界洁净煤研究的热点；
The study of trace elements was focus of clean coal technology in the world.
youdao
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煤中微量元素是世界洁净煤研究的热点；
The study of trace elements was focus of clean coal technology in the world.
youdao