A sharp sword was found buried together with the royal carpenter, which was believed _____himself

  against grave robbers.    [ ]

A. used to defend  

B. being used to defend  

C. to be used to defending  

D. to be used to defend

被电击的非创伤心脏骤停患者中最常见的心律为（）

A.心脏停搏

B.有脉性室性心动过速

C.心室颤动

D.无脉性电活动

E.心动过缓