单项选择题 A crew member has just fallen overboard off your port side. Which action should you take?（）.

单项选择题 （）of the following messages is allowed to be transmitted on the radiotelephone without the authority of the Master.

单项选择题 MV SUDAN/MEAN AT 0200UTC IN POSITION 40.44N 141.52E PASSED A DERELICT ABOUT 40 TONS HALF SUBMERGED AND IS DRIFTING. This cable says that she met with possibly（）.