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

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

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

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

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

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

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

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

Using a file without a handle may result in （）

（）connectors hold best if a wire is accidentally pulled or a connection becomes loose.