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

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.

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

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

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

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

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

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

The Port State Control officer may witness a fire drill carried out by the crew assigned to these duties on the（）

Under MARPOL Code the ship to which it applies has to carry （）