单项选择题
A.the temperature and flow quantity of the exhaust gas from M.E
B.the quantity of steam demanded
C.the rotary speed and the cooling water temperature of main engine
D.efficiency of M.E turbocharger
单项选择题 A purge recovery system is used in a centrifugal air conditioning or refrigeration system to （）
单项选择题 Refrigerant entering the compressor of a refrigeration system should be in which of the following conditions?（）
单项选择题 Flame failure in an automatically fired auxiliary boiler can from a/an （）