单项选择题
Which types of portable extinguisher should you watch for the reflash of the fire?（）
A.foam and water B.CO2 and dry chemical C.dry chemical and water D.foam and CO2
单项选择题 A portable foam fire extinguisher is placed in operation by（）
单项选择题 Before you begin administering artificial respiration, you should be sure the victim（）
单项选择题 If liquid freon should come in with your skin, you should （）
