单项选择题
A.any of (1) and (3)
B.any of (1) and (2)
C.any of (2) and (3)
D.any of (1), (2) and (3)
单项选择题 The device used for low-pressure control and high-pressure cutout on a compressor is called （）.
单项选择题 In a vapor compression refrigeration the evaporating pressure is maintained constant by the action of the （）, which removes vapor from the evaporator at the same rate at which it is formed.
单项选择题 What is the function of thermostatic expansion valve in a compression refrigeration system?（）