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

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

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

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

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

Who is responsible for ensuring that someone is assigned to close the watertight doors in an emergency?（）

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

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

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

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