单项选择题 When you hear three short blasts on the ships whistle and the same signal on the general alarm bells, you （）.

单项选择题 The spreading of fire as a result of heat being carried through a vessels ventilation system, is an example of heat transfer by （）.

单项选择题 Combustible material stored in a compartment adjacent to a compartment where there is a fire may be ignitedThis ignition can occur by （）.