窦性心动过速时，心动周期中缩短最明显的是()
A.快速充盈期
B.等容收缩期
C.减慢充盈期
D.快速射血期
E.减慢射血期
参考答案：A
Lady Wang _____as a secretary for five years in the company, and now she is a general manager of it.
A．has served
B．serves
C．had been serving
D．served
屏蔽状态是火灾报警控制器在屏蔽（指通过控制器使某些部件或功能失效的操作）功能启动后所处的工作状态。（）
