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

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

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

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 （）.

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

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

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

Thermostatic expansion valves can be adjusted for （）.

The rate of heat transfer between the hot and cold fluids passing through a shell-and-tube type heat exchanger will （）.

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