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單項選擇題

A pump is said to have "negative suction head" when the pump is located （）.

A.between the suction and discharge
B.below the liquid supply
C.above the liquid supply
D.any of the above

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單項選擇題

Which of the following pumps are self-priming, and can deal with liquid from a level below the pump? （）
(1) reciprocating
(2) vane
(3) gear

A.（1）only
B.（1）and（2）
C.（1），（2）and（3）
D.（2）and（3）

單項選擇題

Which of the following pumps are self-priming, and can deal with liquid from a level below the pump? （）
(1) reciprocating
(2) rotary
(3) centrifugal

A.（1）only
B.（1）and（2）
C.（1），（2）and（3）
D.（2）and（3）

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