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

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

Which of the diesel engine components listed increase air density and helps to improve engine operating efficiency?（）

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.

Under MARPOL Code the ship to which it applies has to carry （）

Which of the listed governor characteristics will greatly affect the load sharing relationship between paralleled diesel generators?（）

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

If two A.C.generators are to be operated in parallel, the load is distributed evenly by（）

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

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（）