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

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

The condensers located in various stages of a flash evaporator are cooled by（）

To proceed to the assistance of a ship in distress is（）

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

“Insufficiency of manning or insufficiency of certification of seafarers” is an identification of a（）

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.

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

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

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