单项选择题 At night you observe a vessel ahead show three flashes of a white light. This signal indicates that the vessel ahead is（）.

单项选择题 AS SOON AS I HAVE FURTHER INFORMATION I WILL MAKE ANOTHER ANNOUNCEMENT. I ASK YOU KINDLY TO REMAIN CALM. THERE IS NO DANGER AT THIS TIME. These words are likely from（）.

单项选择题 An orange flag showing a black circle and square is a（）.