Heavy wear in a particular area of the inner circumference of a packing ring may be caused by （）.

A salinity indicator is used to determine the （）.

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

Pitting in the suction areas of a centrifugal pump bronze impeller is usually caused by （）.

The rate of heat transfer from a hot region to a cold region is affected most by the （）.

When the steering gear is in operation, you should （）.

The output volume of a positive fixed displacement pump can be changed only by （）.

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

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 （）.

Thermostatic expansion valves can be adjusted for （）.