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

（） is not installed on the main switchboar.

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

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

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

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

Using a file without a handle may result in （）

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

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 treatment of the fuel oils involves storage, heating, filtering and（）