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一、概述近三年来,西方世界金属铅产量逐年下降,1979年总计429万吨,1980年下降到410.6万吨,1981年又下降到392.6万吨,年
I. Overview Over the past three years, the output of lead metal in the western world has dropped year by year, reaching 4.29 million tons in 1979, dropping to 4.106 million tons in 1980 and 3.926 million tons in 1981