单项选择题
A.6 short blasts and 1 long blast
B.long blast mare than 6 short blasts
C.more than 6 short blasts and 1 long blast
D.1 long blast of at least 10 seconds
单项选择题 If you have to abandon ship and enter a life-raft, your main course of action should be （）.
单项选择题 In the first 24 hours after abandoning a vessel, water should be given only to personnel who are（）.
单项选择题 Diesel fuel is relatively safe to handle due to its low volatility, but the fumes will self-ignite and continue to burn steadily if the fuel is heated to the （）.