单项选择题
A.sub-boards B.main switchboards C.emergency switchboards D.distribution boards
How do you treat someone suffering from electrical shoc...
单项选择题How do you treat someone suffering from electrical shock after you secure the source?（）
A.check for respiration B.check for pulse C.treat for shock D.All of the above
Tools with （）handles should be used to check electric c...
单项选择题Tools with （）handles should be used to check electric circuit.
A.plastic B.metal C.stainless steel D.copper
Before doing maintenance on electrical equipment, you s...
单项选择题Before doing maintenance on electrical equipment, you should （）.
A.turn off power first B.turn on power first C.with a test pen in hand D.tell C/E
