心脏正常起搏点位于（）。
A.窦房结
B.房室交界区
C.心房
D.心室末梢普肯耶纤维网
E.心室
参考答案：A
1. The child enjoyed _____ up the wooden bricks then knocking them down.
A. adding B. pushing C. piling D. forming
2. John was very upset because he was _____ by the police with breaking the law.
A. accused B. arrested C. sentenced D. charged
3. It isn't quite _____ that he will be present at the meeting.
A. sure B. right C. exact D. certain
电力系统故障动态记录技术准则》中规定电力故障动态过程记录设备的最低要求的采样速率为每个工频周波采样点不小于（）
A、20点
B、16点
C、40点
D、28点
