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

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

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

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

During the diesel engine running, the water level of F.W expansion tank should normally kept in the （） level of glass tube.

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

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

Flame failure in an automatically fired auxiliary boiler can from a/an （）

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

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