单项选择题
A.Rose box B.Sea chest or spool piece C.Sluice valve D.Fire pump stuffing box
Fires involving combustible metals are classified as （）...
单项选择题Fires involving combustible metals are classified as （）.
A.class "A" fires B.class "B" fires C.class "C" fires D.class "D" fires
Which of the following gases represents the greatest th...
单项选择题Which of the following gases represents the greatest threat to personnel safety in an engine room where the exhaust is leaking from a diesel engine?（）
A.Carbon dioxide B.Carbon monoxide C.Carbon trioxide D.Hydrogen sulfide
Seawater may be used for drinking water （）.A.at a maxim...
单项选择题Seawater may be used for drinking water （）.
A.at a maximum rate of two ounces per day B.after mixing with an equal quantity of fresh water C.if gather during or immediately after a hard rain D.under no circumstance
