单项选择题
Each part of the fire-main system located on an exposed deck must be（）.
A.protected against freezing B.locked to prevent theft C.numbered sequentially D.pressurized at all times
单项选择题 Each hose in the fuel transfer system for helicopter refueling must meet the standards of the（）.
单项选择题 Each hand portable fire extinguisher must be marked with（）.
单项选择题 Each fireman’s outfit and its spare equipment on a vessel must be stowed（）.
