A casualty report of an intentional grounding of a ship is required under what condition?（）

单项选择题A buoy with a composite group-flashing light indicates a(n)（）.

A.bifurcation
B.fish net area
C.anchorage area
D.dredging area

单项选择题A block and tackle is “rove to advantage”. This means that the（）.

A.blocks have been overhauled
B.hauling parts of two tackles are attached
C.hauling part leads through the movable block
D.hauling part leads through the standing block

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

A.actual total loss
B.constructive total loss
C.general average
D.particular average

单项选择题A backlash below a lock is defined as a（）.

A.current setting your vessel on the wall
B.current setting into the lock chamber
C.an eddy working along the lower guide wall
D.current setting counterclockwise

单项选择题A “spring line” is（）.

A.any wire rope used for mooring
B.a fire-warp
C.a mooring line running diagonally to the keel
D.a mooring line perpendicular to the keel