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

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

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

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

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

Which one is NOT the ‘clear grounds’ for a more detailed inspection?（）

The ISPS Code consists of a mandatory section-Part A, which shows（）

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

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 main purpose of port State control is not to（）