642.This is the minimum concentration of flammable vapors in air below which propagation of flame does not occur on contact with a source of ignition ( )

295.Jack was down in the mouth because he missed his plane ( )

294.释放高温大翼防冰气体会导致人员受伤。( )

293.确保探头的温度升高到超过 500 摄氏度。( )

292.If the instructions give a warning about dangerous pressure, do not open the container( )

291.通过三个循环操作作动筒 ( )

290.The girt bar attached to the escape slide which engages brackets on the floor for automatic slide operation when the doors are opened ( )

289.The purpose of the CSD is to convert the variable speed of the engine to a constant speed for the driven of the generator to produce AC power at constant frequency ( )

288.The document points out that the FAA should be contacted prior to any alterations on airplane to insure that airworthiness of the airplane is not violated ( )

287.巡航性能显示的格式由飞机制造商决定。( )

286.Doorstop at forward external fuselage servicing door is protruding( )