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

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

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

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

Which of the listed pumps is NOT a positive displacement pump?（）

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

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

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

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

A salinity indicator is used to determine the （）.