只有在哪种情况下窦房结细胞才具有兴奋性()A．钙通道处于备用状

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问题单项选择题

只有在哪种情况下窦房结细胞才具有兴奋性()

A．钙通道处于备用状态

B．钠通道处于激活状态

C．钠通道处于备用状态

D．钙通道处于激活状态

E．钾通道处于备用状态

答案

参考答案：A

选择题

It is politely _____ by the hotel management that loud music _____ after 11 o'clock at night. [ ]

A. requested; were not played

B. asked; not to play

C. requested; not be played

D. asked; did not play

问答题论述题

试分析朱利安的比较教育思想及其历史贡献。