题目内容

采煤工作面回采率应符合哪些要求?

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高炉的硫负荷

A vessel’s Certificate of Documentation().

A. may be retained by the owner at the home port OR kept on the vessel
B. must be posted under transparent material in the pilothouse
C. must be carried on board
D. must be kept on file at the corporate offices of the owner or operator

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