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

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

Thermostatic expansion valves can be adjusted for （）.

One cause of high head pressure occurring in a refrigeration system can be （）.

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 （）.

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

An excessive charge of refrigerant in an air-cooled refrigeration system can cause （）.

If the suction pressure at the refrigeration compressor is below normal, the cause can be（）.

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

Who is responsible for ensuring that someone is assigned to close the watertight doors in an emergency?（）