secondary tin再生锡secondaryadj.次要的；从属的；中等教育的n.副手；次要位置secondary hematite二次赤铁矿Secondary entities二级单位secondary corditis继发性声带炎secondary waterway次要水道secondary nutrient次级营养素secondary activity(限制酶的)次级活性secondary antibody第二抗体secondary yolk sac次级卵黄囊secondary standard副基准secondary particle二级粒子