单项选择题
A.Masthead lights and sidelights
B.One sidelight，the masthead lights and stern light
C.Both sidelights
D.Stern light
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（）.
单项选择题 An intermediate spring is（）.