On tank vessels equipped with power operated cargo tank valves, the type of power operator most commonly used is （）.

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

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

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

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

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

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

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

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

If the suction pressure at the refrigeration compressor is below normal, the cause can be（）.