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

A salinity indicator is used to determine the （）.

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

A grease gun is generally used to lubricate a （）.

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

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

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 （）.

Which of the following statements is correct concerning heat transfer?（）

If the thermal bulb of an expansion valve is incorrectly placed at the center of the coil instead of the end, it will （）.