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 （）.

An increasing head pressure in a refrigeration system, without any corresponding change in the cooling water inlet temperature, would probably 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 （）.

Heavy wear in a particular area of the inner circumference of a packing ring may be caused by （）.

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

The output volume of a positive fixed displacement pump can be changed only by （）.

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

The temperature differential occurring between the inlet temperature of the fluid to be cooled and the outlet temperature of the cooling medium in a shell-and-tube heat exchanger is greatest in which of the flow designs listed?（）

If the viscosity of the liquid being transferred remains constant as the discharge pressure increases, the rotary pump （）.