three DOFs三自由度threenum.三n.三；三个adj.三个的three innovations edueation三创教育three-phase symmetry load三相对称电源three dimensional structure立体结构three-ply steel moldboard三层钢犁壁three dimensions of context三维语境three-dimensional warfare三度空间战three-arm combined beater三翼综合打手three-dimensional nucleus三维晶核three dimensional holograph三维全息术Three Response Optimization三响应优化