单项选择题
When your vessel enters thick fog，she should sound（）every two minutes in accordance with these Rules.
A.one short blast B.one prolonged blast C.two short blasts D.three short blasts
单项选择题 Where does the look-out man stand?（）.
单项选择题 While underway at night you observe a vessel’s range lights in line off your starboard beam． You should（）.
单项选择题 You are in restricted visibility and hear a fog signal forward of the beam. Nothing appears on your radar screen. You must（）.
