threestepadj.三级的threenum.三n.三；三个adj.三个的three-in-one furnace“三合一”炉three states of nitrogen三氮Three Outlooks education“三观”教育three-phase power flow三相潮流three-dimensional test三维试验three-terminal contact三端子接点three- phase component三组分three-body interaction三体作用three coordinate measure三坐标测量three-dimension coding三维编码