单项选择题
A synonym for chloroform is（）.
A.trichloromethane B.sulfuric chlorohydrin C.chlorine gas D.4-methyl phenol
单项选择题 A safe fuel system must（）.
单项选择题 A petroleum liquid has a flash point of 135°Fahrenheit. This liquid is classed as a grade （）.
单项选择题 A flame screen（）.
