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

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

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

The control mode in which the final control element is moved from one of two flexed positions to the other is known as （）.

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

A salinity indicator is used to determine the （）.

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 （）.

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

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

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