A.hollow tube surrounding the propeller used to improve thrust B.nozzle attached to a firefighting hose C.intake valve on a diesel engine D.piston cylinder on a diesel engine
单项选择题A hydraulic accumulator aboard a ship 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 fuel-air mixture below the lower explosive limit is too().
A.rich to burn B.lean to burn C.cool to burn D.dense to burn