dualadj.双重的；成双的n.双数dual card双联卡片,传票卡片,对偶卡片dual gear二联齿轮dual norm对偶范数dualtyredadj.双轮的dual CPUs双CPUdual drumadj.双筒的dual boot双重引导dual plan[经] 双重法, 双重标准制dual gridadj.双栅的Dual dock双港