单项选择题
What normally helps in detecting escaping gas? （）
A.Running hand along pipe B.Red flame C.Odor D.Increase the line pressure
单项选择题 What is used to test a tank for oxygen content?（）
单项选择题 What is the proper first aid for LPG in the eye? （）
单项选择题 Upon release to the atmosphere，LFG readily（）.
