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

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

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

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

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

A pressure drop through the refrigerant liquid line may cause （）.

Which of the following problems could cause the high pressure cutout switch to shut down the compressor in a refrigeration system?（）

If the viscosity of the liquid being transferred remains constant as the discharge pressure increases, the rotary pump （）.

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

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 （）.