单项选择题
The sign used to caution persons approaching the gangway of a tank barge during cargo transfer reads（）.
A.warning, keep off,stay clear B.danger, do not board C.warning, no smoking, no open lights, no visitors D.dangerous cargo being transferred
单项选择题 What is not accepted as the required shipping paperson a manned and loaded tank barge?（）.
单项选择题 What will be accepted as the shipping papers for an unmanned tank barge but will not be accepted if the tank barge is manned?（）.
单项选择题 Which data is not painted on the bow of a lifeboat?（）.
