secondary end次级端secondaryadj.次要的；从属的；中等教育的n.副手；次要位置secondary superheater二次过热器secondary leather cup副皮碗secondary propagation次级繁殖secondary bifurcation次级分岔secondary axial plane第二眼位轴平面secondary loan crisis次贷危机secondary fault basin次级断裂盆地secondary trochoblast次级成纤毛细胞secondary carbon atom仲碳原子secondary lung lobule二级肺小叶