A “fifteen-pound” CO2 extinguisher is so called because（）.

A “check” line is（）.

A chain bridle is used when towing astern because it（）.

A chart with a scale of 1:80，000 would fall into the category of a（）.

A “full service” Loran-C receiver will provide（）.

A CO2 extinguisher on a ship which has lost 10% of its charge must be（）.

A conscious victim who has suffered a blow to the head has symptoms that indicate the possibility of concussion. If the patient feels no indication of neck or spine injury，recommended treatment would include（）.

A backlash below a lock is defined as a（）.

A ballasted vessel sinks enroute to a dry dock. Under these circumstances，the vessel’s owner can claim（）.

A common class of wire rope used for mooring is the 6x19 class. What does the 6 represent?（）