单项选择题
A.More than six short blasts and one long blast on the whistle
B.Continuous blast of the ships whistle for a period of not less than 10 seconds supplemented by the same signal on the general alarm
C.Three short blasts of the whistle supplemented by the same signal on the general alarm
D.More than six short blasts and one long blast on the whistle supplemented by the same signal on the general alarm
单项选择题 To extinguish an electrical fire, you should use （）.
单项选择题 If a CO2 fire extinguisher is not readily available, which of the listed fire extinguishers would be best suited to combat a small electrical fire in a switchboard?（）
单项选择题 You hear the general alarm bells and ships whistle sound for over 10 secondsTraditionally, this is the signal for （）.