threefoleadj.三倍；增加二倍；三重的；三方面的；三次adv.三倍；增加二倍；三重地；三方面的；三次threenum.三n.三；三个adj.三个的three-quarters pack[医] 四分之三裹法(上至腋部)three-tray tool box三层工具箱three-way telephone传真fax三方通话three--line table三线表three-terminal link三端连接three circles theorem三圆定理three singing methods三种唱法three states feedback三状态反馈three-string-beam三弦梁three-level section三点折线断面,三点断面