单项选择题
A.positive displacement B.non-positive displacement C.mixed-flow D.axial-flow
（） are more suitable for large quantities at low pressu...
单项选择题（） are more suitable for large quantities at low pressure.
A.Reciprocating pumps B.Rotary pumps C.Centrifugal pumps D.Gear pumps
The various pumps and lines are （） to some extent so th...
单项选择题The various pumps and lines are （） to some extent so that each pump can act as an alternative for another.
A.interlocked B.interconnected C.interfered D.interacted
According to the way the steering gear is operated, the...
单项选择题According to the way the steering gear is operated, the steering gear may be divided into: hand - steering, （） and automatic steering.
A.hydraulic steering B.follow-up steering C.remote control steering D.air controlled steering
