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

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

A salinity indicator is used to determine the （）.

Low compressor head pressure in a refrigeration system can be caused by（）.

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

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

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 （）.

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

The temperature differential occurring between the inlet temperature of the fluid to be cooled and the outlet temperature of the cooling medium in a shell-and-tube heat exchanger is greatest in which of the flow designs listed?（）

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