生理情况下心脏的正常电活动起源于（）。
A.浦肯野纤维
B.希氏束
C.房室结
D.心内膜细胞
E.窦房结
参考答案：E
We got lost in the forest and decided to remain _____ we were and waited for rescue．
A．how
B．what
C．where
D．who
投保提示书应当至少包括的内容有哪些？
