使用电钻时，必须戴（）。用压杆电钻时，压杆应与电钻（），压杆固定点应（）。
参考答案：绝缘手套；垂直；牢固
____for the doctor's careful treatment, he____till last year.
A．If it is not; can't live
B．Were it not; couldn't live
C．Had it not been; couldn't have lived
D．If they were not ; couldn't live
腰椎牵引最适用于（）
A.腰椎管狭窄
B.腰椎小关节紊乱
C.腰椎滑脱
D.腰椎间盘突出症
E.腰背筋膜炎
