单项选择题
A.Washing water should be recirculated if possible because it has the same electric potential as the cargo tank being cleaned
B.The hoses to portable cleaning machines should be disconnected before the machines are removed from the tank
C.The principal hazard with steaming cargo tanks is raising the ambient temperature above the flame point of the cargo residue
D.Steam cleaning and water washing are both capable of generating electrostatic charges within a tank
单项选择题 You are carrying triethylamine，methyl methacrylate and isoprene in your multiple-product tanker. Which of the following statements is true? （）
单项选择题 You are carrying cargoes of crotonaldehyde，phosphoric acid，and morpholine on your multiple-product tanker. Which of the following statements is TRUE? （）
单项选择题 You are approaching another vessel and see that she has the signal flag “J” hoisted. What should you do?（）