单项选择题
A.During annual repair
B.Usually during dock repair
C.Before sea trial
D.After 5 years from last annual survey
单项选择题 （）, where a ship is refitted for a different use.
单项选择题 （）, where extensive work, particularly to the ship’s structure may be repairedThese are the result of groundings collisions and other accidents.
单项选择题 （）, where minor repairs are carried out with a ship service, often during a stay in portThis may be remote from a ship repair site.