单项选择题
A.readjust the relief valve
B.throttle the suction line
C.throttle the discharge valve
D.open the priming line
单项选择题 An AC synchronous transmission type remote steering control system consists of a （）.
单项选择题 In which of the areas listed would you expect to find the highest salt concentration in a flash evaporator?（）
单项选择题 The component of a refrigerating system in which the refrigerant vaporizes and absorbs heat is known as the （）.