单项选择题
Aboard a survival craft，ether can be used to（）.
A.start the engine in cold weather B.aid in helping personnel breathe C.prime the sprinkler system D.prime the air supply
单项选择题 A towline should be fastened to（）.
单项选择题 A shipmate chokes suddenly，cannot speak，and starts to turn blue. You should（）.
单项选择题 A right-handed propeller will cause the survival craft to（）.
