单项选择题
Which of the fire extinguishers listed is to be weighed annually and sent ashore for recharging if the weight loss exceeds 10% of the weight of a full charge?（）
A.Foam B.Soda acid C.Dry chemical D.Carbon dioxide
单项选择题 A carbon dioxide fire extinguisher has been partially discharged, and should be immediately （）.
单项选择题 Which of the listed fire extinguishers cannot be easily recharged aboard ship?（）
单项选择题 When checking the liquid level in a tank, you should position yourself （）.
