威胁网络安全的主要因素有() ["自然灾害","意外事故","计算机犯罪","“黑客”行为"]
患者,男,43岁。两耳轰鸣,按之不减,听力减退,兼见烦躁易怒,咽干,便秘,脉弦。治疗应首选() ["A.手、足太阴经穴 ","B.手、足少阴经穴 ","C.序手、足少阳经穴 ","D.手阳明经穴 ","E.足太阳经穴"]
进料加工
第一个克隆的动物是() ["牛","猪","羊","狗"]
来料加工
在定位板与模具总厚度为50mm的工件一加工一个定位孔,其大端直径D=16mm,锥度为1:50,问应先钻一多大直径的孔?