单项选择题
The use of sinking and dispersing agents for the removal of surface oil is （）.
A.the most common method used in the United States B.too expensive for common use C.generally safe to sea life D.generally harmful to sea life
单项选择题 One of the disadvantages of using carbon dioxide to extinguish a fire in an enclosed space is （）.
单项选择题 A fire involving aluminum powder would be a class （）.
单项选择题 Which of the following components provides a direct source of seawater for the fire main system?（）
