电子舱通风蒙皮交换器进口旁通活门何时打开（）
A.在开路状态时；
B.在闭路或中间状态，气流量大于要求值时；
C.在电子舱温度大于35℃时
参考答案：B
It was not until fish ____ that the villagers realized the importance of protecting the river. [ ]
A. died away
B. died off
C. died from
D. died out
酌量性固定成本相对于业务量和特定的管理决策行为均是固定的。
