If your vessel is underway in fog and you hear one prolonged and three short blasts，this is a （）.

单项选择题If there is sufficient sea room，alteration of（）may be the most effective action to avoid close-quarters situation.

A.speed and course
B.speed alone
C.course alone
D.speed or course

单项选择题If there is any doubt as to the proper operation of a radar，which statement is TRUE?（）.

A.Only a radar expert can determine if the radar is operating
B.All radars have indicator lights and alarms to signal improper operation
C.A radar range compared to the actual range of a known object can be used to check the operation of the radar
D.The radar resolution detector must be energized to check the radar

单项选择题If it becomes necessary for a stand-on vessel to take action to avoid collision，she shall NOT，if possible，（）

A.decrease speed
B.increase speed
C.turn to port for a vessel on her own port side
D.turn to starboard for a vessel on her own port side

单项选择题Any vessel（）any other shall keep out of the way of the vessel（）.

A.overtaking／overtaken
B.being overtake／being overtaken
C.overtaking／being overtaken
D.being overtaking／overtaken

单项选择题Any alteration of course and／or speed to avoid collision shall，if the circumstances of the case admit，（）to another vessel observing visually or by radar.

A.be large enough to be readily apparent
B.be a succession of small alterations
C.be with due regard to the power and speed of the vessel
D.leave sufficient room for the other vessel to take action