When does auxiliary burner of incinerator put into operation? （）Ⅰ. start incinerator when it is coldⅡ. the sludge for dealing with is littleⅢ. the sludge for dealing with is largeⅣ. the water and impurity in sludge are too muchⅤ. the temperature in incinerator is lowⅥ. dealing with little solid rubbish

The cetane rating of diesel fuel is an indication of the （）

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

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

The additional mark （）in the Classification Certificate for Machinery means propulsion apparatus is remotely controlled on the navigating bridge control station, and engine assembly control station is unmanned periodically.

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

One of the reasons that cause oil flowed from sludge outlet of a self-cleaning separator is（）

If separating effect is not good, which measure should be taken （）

Which of the following items don’t belong to dock repair works?（）

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