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

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

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

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

The shipboard oil pollution emergency plan will be invalid after （）

The flash point of a residual fuel oil should be used to determine the highest temperature to which oil may be heated（）

（） is not installed on the main switchboar.

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.

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

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