单项选择题
Which of the following pumps are self-priming, and can deal with liquid from a level below the pump（） (1) ejector (2) screw (3) centrifugal
A.(1)only B.(1)and(2) C.(1),(2)and(3) D.(2)and(3)
单项选择题 In （） pumps a closed discharge valve will cause bursting discharge pressure.
单项选择题 The volute pump is one in which the impeller （）.
单项选择题 Which of the following pumps belongs to centrifugal pump?（）
