单项选择题
In a centrifugal Freon refrigeration system, the overall capacity of the system is increased by（）
A.opening more bypass lines B.opening additional expansion valves C.adding refrigerant D.speeding up the machine
单项选择题 The main distribution duct in an air conditioning system which contains the cooling coils and filters is called the（）
单项选择题 If a compressor runs continuously, the cause might be a（）
单项选择题 Which of the following would not cause high suction pressure?（）
