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

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.

As soon as a diesel engine has started, which of the listed engine operating parameters should be checked FIRST?（）

To proceed to the assistance of a ship in distress is（）

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

By comparing the exhaust gas temperature of each cylinder, the operator can determine if the load is balanced throughout the engine. The device most commonly used is a（）

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

Flame failure in an automatically fired auxiliary boiler can from a/an （）

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

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