单项选择题 An overtaking situation at night would be one in which one vessel sees which light(s) of a vessel ahead?（）

单项选择题 An oiler was badly burned and you are communicating with a passenger ship that has a doctor and hospital on board. You want to rendezvous in a certain position so the oiler can be evacuated for medical treatment. Which code should your message contain?（）

单项选择题 An isotherm is（）.