If the relief valve on the discharge side of a hydraulic pump lifts, the cause could be （）.

Which of the listed pumps is NOT a positive displacement pump?（）

The general purpose of a heat exchanger is to （）.

A gradual decrease in the discharge pressure of an operating hydraulic pump can be caused by （）.

An internal bypass is provided on some hydraulic system suction strainers to help reduce the possibility of （）.

The major source of chemical contaminants in hydraulic fluid is （）.

The usual symptoms of cavitation in a centrifugal pump is （）.

If you are given the job of adding hydraulic fluid to a mooring winch, and are not certain as to the type of fluid to use, you should （）.

When a refrigeration compressor has developed a high head pressure as a result of a refrigerant overcharge, you should （）.

On tank vessels equipped with power operated cargo tank valves, the type of power operator most commonly used is （）.