安装在室内的橇装式发电机要预留出（）有效区域。
A、灭火
B、开门
C、维修
D、通风
参考答案：B
Her _______ smile suggested that she was very _______ with the answer.
A．satisfying；satisfied
B．satisfied；satisfying
C．satisfied; satisfied
D．satisfying；satisfying
柴油发电机组的启动装置，由于自备发电机组均为应急所用，因此首先要选有自启动装置的机组，一旦城市电网中断，应在( )内启动且供电。
A．5sB．10sC．15sD．20s
