单项选择题
Which of the following types of hydraulic pumps would be used in a steering system?（）
A.Lobe B.Screw C.Radial piston D.Volute
单项选择题 Which of the following statements is true concerning centrifugal pumps?（）
单项选择题 The temperature of the refrigerant in the evaporator coil depends mostly upon the （）.
单项选择题 Refrigerant is circulated through a refrigeration system by the （）.
