单项选择题
Repair of vital machinery and services on a ship should be accomplished（）.
A.after control of fire，flooding，and structural repairs B.immediately C.after control of fire，but before control of flooding D.after stability is restored
单项选择题 Initial stability refers to stability（）.
单项选择题 Initial stability of a vessel may be improved by（）.
单项选择题 In astern towing，a tow span，also called the tow bar or towing arch，is used to（）.
