（） is not installed on the main switchboar.

（）connectors hold best if a wire is accidentally pulled or a connection becomes loose.

Refrigerant entering the compressor of a refrigeration system should be in which of the following conditions?（）

The main purpose of port State control is not to（）

The Port State Control officer may witness a fire drill carried out by the crew assigned to these duties on the（）

Using a file without a handle may result in （）

（）are used to digest the sewage to produce innocuous sludge in a biological sewage treatment plant.

Thermostatic steam pressure reducing valves are used in the fuel oil service system to control the（）

Which of the diesel engine components listed increase air density and helps to improve engine operating efficiency?（）

If two A.C.generators are to be operated in parallel, the load is distributed evenly by（）