单项选择题
Oily rags stored in a pile that is open to the atmosphere are a hazard because they may（）.
A.deteriorate and give off noxious gasses B.spontaneously heat and catch fire C.attract lice and other vermin and serve as a breeding ground D.None of the above
单项选择题 Normally，potable water systems are connected directly to the（）.
单项选择题 Line throwing apparatus aboard ship must contain（）.
单项选择题 In order for the automatic lifeboat drain to operate properly（）.
