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

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

To shut down a diesel engine after it exceeds the set maximum speed，which type of device listed should be used?（）

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

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

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

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

By comparing the exhaust gas temperature of each cylinder, the operator can determine if the load is balanced throughout the engine. The device most commonly used is a（）

For a given exhaust gas boiler, what is the quantity of its evaporation mainly determined?（）

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.