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單項選擇題

（） are used to limit the pressure in any particular portion and mainly control the pressure after the valve.

A.Relief valves
B.Check valves
C.Safety valves
D.Reducing valve

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單項選擇題

Among the basic categories of equipment, which of the following is used to convert hydraulic energy into continuous rotary motion?（）

A.Hydraulic pumps
B.Valve
C.Hydraulic cylinders
D.Hydraulic motors

單項選擇題

Among the basic categories of equipment, which of the following are used to convert mechanical into hydraulic energy?（）

A.The hydraulic pumps
B.Valves
C.Hydraulic cylinders
D.Hydraulic motors

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