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

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

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

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

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

The main purpose of port State control is not to（）

Cold weather starting of a diesel engine may be made easier by（）

“Insufficiency of manning or insufficiency of certification of seafarers” is an identification of a（）

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

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