单项选择题
A.close and seal around the drill pipe B.close and seal around casing C.cut off pipe inside the preventer stack D.close and seal around drill collars
The rated operating time of a self-contained breathing ...
单项选择题The rated operating time of a self-contained breathing device may be reduced in actual use because of（）.
A.pressure differences in the atmosphere B.the length of the hose attached to the facepiece C.the physical exertion of the person wearing the device D.spaces containing poisonous vapors
The radiotelephone urgency signal is（）.A.maydayB.pan pa...
单项选择题The radiotelephone urgency signal is（）.
A.mayday B.pan pan C.securite D.seelonce feenee
The Muster List (“Station Bill”) shows each person’s li...
单项选择题The Muster List (“Station Bill”) shows each person’s lifeboat station，duties during abandonment，basic instructions，and（）.
A.all emergency signals B.instructions for lowering the lifeboats C.the time each weekly drill will be held D.work schedule
