A purge recovery system is used in a centrifugal air conditioning or refrigeration system to （）

As soon as a diesel engine has started, which of the listed engine operating parameters should be checked FIRST?（）

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

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 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.