但是，铅也可以来自其他方面，如冶炼厂，铁和炼钢业，航空燃料。
But lead can also come from other sources such as smelters, the iron and steelmaking industry, and aircraft fuel.
传教士曾引进过拉丁文铅活字印刷和铜雕版印刷，但对中国印刷业没有产生实质性影响。
Though the missionaries introduced lead type printing and bronze block printing in latin, the introduction did not make substantive impact on Chinese printing industry.
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