单项选择题
The bilge pump on a fishing vessel（）.
A.must be fixed if the vessel exceeds 12 meters in length B.may be used as a fire pump C.must be portable if there are more than 4 watertight compartments D.must be capable of pumping at least 450 gpm
单项选择题 The best method of extinguishing a class A fire is to（）.
单项选择题 The BEST method of applying foam to a fire is to（）.
单项选择题 The atmosphere in a tank is too lean if it is（）.
