单项选择题
A.can be observed by radar
B.has determined that risk of collision exists
C.is sounding a fog signal which can be heard on the other vessel
D.can be observed visually from the other vessel
单项选择题 A vessel is in sight of another vessel when（）.
单项选择题 A vessel is approaching from dead ahead． Both of her sidelights are visible and her range lights are in line. Which of the following could you do first?（）.
单项选择题 A vessel has sustained damage in a collision with another vessel. It is necessary to have a Seaworthy Certificate before the vessel sails. Who will issue this certificate?（）