例： British and American metallurgists arrived on the patent office doorstep at about the same time in 1948 with their processes for manufacturing a new form of cast iron called ductile iron, a marvelous product that could be made using most of the available equipment and technology of the gray iron foundry and had some special physical and economic advantages setting it apart from gray and malleable irons and forged or cast steels. 冶金学家 球墨铸铁 可锻铸铁 例： 例： A 、根据词类，辨明词义 1、Aluminium is a light metal.
