AN ILLNESS PREFERABLY OF AN INFECTIOUS NATURE SEIZING MORE THAN TWO PERSONS ON BOARD AT THE SAME TIME defines（）.

A.start the engine in cold weather
B.aid in helping personnel breathe
C.prime the sprinkler system
D.prime the air supply

A.the chocks at the bow of a towed vessel
B.the most forward，centermost point of a towed vessel such asa sturdy bow rail
C.the mast of a towed sailboat
D.a secure fitting near the bow of the towed vessel

A.perform the Heimlich maneuver
B.make the victim lie down with the feet elevated to get blood to the brain
C.immediately administer CPR
D.do nothing until the victim becomes unconscious