double-un.字母wdoubleadj.双重的；成双的；两倍的v.翻一番；使 ... 加倍n.两倍；双份double-coincidence switch双重合开关,二重符合开关double- season early rice双季早稻double-action disc harrow(双列圆盘靶) 双功圆盘靶double network transmission双网传输double-variable principle双变量原理double scoop type excavator双斗式挖土机double flow lines operation双流水线作业double-side hacksaw blade双面刃钢锯条double probe testing method双探头探伤法double-rail track circuit双轨线路