单项选择题
What is the best instrument for establishing a safe working area before welding in a confined space? （）
A.An oxygen indicator
B.A combustible gas indicator
C.A combination combustible gas and oxygen indicator
D.A flame safety lamp
点击查看答案&解析
相关考题
-
单项选择题
What is the BEST conductor of electricity?（）
A.Carbon dioxide
B.Distilled water
C.Fresh water
D.Salt water -
单项选择题
Upon completion of fueling a gasoline driven vessel it is necessary to（）.
A.keep ports，doors，windows，and hatches closed
B.start engines immediately
C.ventilate before starting engine
D.None of the above -
单项选择题
There are（）rats on board.
A.not
B.no
C.any
D.none
