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

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

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

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

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

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

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.

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

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

Using a file without a handle may result in （）