请帮忙分析下这个GRE阅读句子the processing of ores introduced poorly controlled changes in the concentrations of minor and trace elements in the resultingmetal.请着重分析下此句的主谓宾,尤其是trace是个什么成分?

问题描述:

请帮忙分析下这个GRE阅读句子
the processing of ores introduced poorly controlled changes in the concentrations of minor and trace elements in the resultingmetal.请着重分析下此句的主谓宾,尤其是trace是个什么成分?