extension net外延网extensionn.延长；伸展；延期；扩充；观念发展；增强n.电话分机；特别课程n.[计]文件名Extension of an Inequality Guess一个不等式猜想的推广extension arbor for drill holder钻夹头接长杆extension of nerve centre system中枢神经系统延伸extension of insurance liability扩展保险责任extension hyper graph data model扩展超图数据模型extension of module homomorphism模同态延拓extension arbor for shell reamer套式铰刀接长杆extension of time for completion完工时间的延长extension matter-element model可拓物元模型extension field of finite degree有限次扩张域