胃肠平滑肌基本电节律的产生可能是由于（）。
A. Ca2+跨膜扩散
B. K+跨膜扩散
Cl﹣跨膜扩散
D. Na+跨膜扩散
E. 钠泵活动的周期性变化
如果患者疑为急性心肌梗死.但胸痛超过24h，最好选择下列哪项进行检查（）。
A. cTn
B. LDH
C. α-HBDH
D. CK
E. AST
When the engine room is put in standby condition, the engineer in charge of the watch need not to（）
A. ensure all machinery which may be used during maneuvering is in ready
B. ensure an adequate reserve of power is available for steering gear and other requirements
C. keep the main propulsion unit controls continuously attended when in the manual mode of operation
D. ensure all machinery which may be used during maneuvering is running stably
所谓战略失效，是指企业战略实施的结果偏离了（）和战略管理的理想状态。
A. 战略目标
B. 战略重点
C. 战略控制范围
D. 企业使命
微信支付 
支付宝支付