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

Engine parameters shall be corresponded to NOx Technical Files. This is required by （）

Cold weather starting of a diesel engine may be made easier by（）

Using a file without a handle may result in （）

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.

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

Diesel engine air start system check valves are opened by （）

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

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