单项选择题
A vessel not using a traffic separation scheme shall avoid（）by as wide margin as practicable.
A.them B.that C.this D.it
单项选择题 A vessel not using a traffic separation scheme shall avoid it by as（）as is practicable.
单项选择题 Two short blasts of the whistle have all of the following meanings except（）.
单项选择题 Under international rules（）.
