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

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

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

A salinity indicator is used to determine the （）.

When a refrigeration compressor has developed a high head pressure as a result of a refrigerant overcharge, you should （）.

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

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

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

Thermostatic expansion valves can be adjusted for （）.

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