单项选择题
The thermal expansion valve responds to the（）
A.amount of superheat in the vapor leaving the coil B.amount of superheat in the liquid C.temperature in the evaporator coils D.pressure in the evaporator coils
单项选择题 The thermostatic valve has a throttling action, that is to say the valve can（）
单项选择题 When the refrigeration demand is small,（）
单项选择题 When the heat load begins to increase, the needle valve of an expansion valve will（）
