单项选择题
Which hazard probably would NOT be encountered when entering an empty but uncleaned fish hold?（）
A.Lack of oxygen B.Methane gas C.Hydrogen sulfide gas D.Carbon monoxide
单项选择题 When starting CPR on a drowning victim，you should（）.
单项选择题 When carrying out a parallel track search pattern，the course of the search units should normally be which of the following?（）
单项选择题 VHF Channel 6 is used exclusively for what kind of communications?（）
