Which of the problems listed would came the discharge temperature of an R-12 refrigeration compressor to increase?（）

The amount of fluid friction or internal friction inherent in a mineral lubricating oil is reflected as a measure of its （）.

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

A grease gun is generally used to lubricate a （）.

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

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?（）

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

If the relief valve on the discharge side of a hydraulic pump lifts, the cause could be （）.

The general purpose of a heat exchanger is to （）.