单项选择题
Control valves of a CO2 system may be located within the protected space when（）.
A.it is impractical to locate them outside B.there is also a control valve outside C.the CO2 cylinders are also in the space D.an automatic heat-sensing trip is installed
单项选择题 CO2 cylinders，which protect the small space in which they are stored must（）.
单项选择题 CO2 cylinders equipped with pressure actuated discharge heads will discharge automatically when（）.
单项选择题 Automatic mechanical ventilation shutdown is required for CO2 systems protecting the（）.
