twolinkn.两段线路twonum.二；两个two-hole coupler双孔耦合器two-phase selsyn二相自动同步机Two machine system两机系统Two-Step Cluster两阶段聚类two-position key二位电键two-lobe chamber双弧工作室two-pulse lasers二束脉冲激光two peak generator双峰(X线高压)发生器two - mode field双模光场two-state theory二态学说