A screw pump belongs to （） according to its working principle.
Which of the following pumps belongs to centrifugal pump?（）
Under rotary pumps are the gear, （）, cam-and-piston and screw types.
Which of the following pumps will build up a bursting pressure or stall their motors if the discharge valves are closed?（） (1) gear (2) centrifugal (3) screw
Pitting in the area close to the pitch line and on the same end of each gear tooth of a reduction gear unit would be caused by （）
In an electro-hydraulic steering gear system, when will the variable displacement pump be placed on stroke?（）
Defective timing gear in a diesel engine may lead to （）.
The oil in a cargo winch gear box should be sampled periodically to （）.
A Cisco Catalyst switch can belong to how many VTP domains？ （）
The control rod of a steering gear pump is attached at its outer end to （）.
Which statement comparing a shipboard crane to conventional gear is TRUE（）.
The amount of fluid delivered by a gear pump can be regulated by （）.
Gear pumps are （） type because they discharge a near constant amount of liquid regardless of pressure.
Positive displacement, helical gear pumps are well suited for pumping oil because （）
Some medium and high-speed diesel engines require reduction gear units to provide a useful propeller speedIn most reduction gears, the bull gear（）
The gear and screw pumps are classified as （）.
The gear, screw, and vane pumps are all classified as （）.
A pump is said to have "negative suction head" when the pump is located （）.
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
45 is belong to () at the stages in a person's life.
Which of the following belong to the characteristics of a company profile? ( )
“exchange among customers” belongs to e-business. （)A．正确B．错误
Which one Not belongs to Soft skill____A.Leadership
