The cetane rating of diesel fuel is an indication of the （）

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

Refrigerant entering the compressor of a refrigeration system should be in which of the following conditions?（）

Engine parameters shall be corresponded to NOx Technical Files. This is required by （）

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

Diesel engine air start system check valves are opened by （）

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

Using a file without a handle may result in （）

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

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