Jackup mast for marine drilling operation realizes hoisting of the mast by means of the pulley mechanism on the lower part of the mast.是什么意思_Jackup mast for marine drilling operation realizes hoisting of the mast by means of the pulley mechanism on the lower part of the mast.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句