单项选择题
A hydraulic accumulator is designed to（）.
A.store fluid under pressure B.act as a fluid reservoir C.provide overpressure relief D.replenish fluid to a system
单项选择题 A fishing vessel that is required to have a fireman’s outfit，must have all of the following in the outfit except a（）.
单项选择题 A fire starting by spontaneous combustion can be expected in which condition?（）
单项选择题 A double male coupling is one that（）.
