单项选择题
A.as it warms up it becomes heavier than air B.the way it reacts with sea water C.the strong odor it produces D.its low temperature causes frostbite or freezing
0pen ullage holes in tanks which are not gas-free must ...
单项选择题0pen ullage holes in tanks which are not gas-free must be protected by（）.
A.PV valves B.warning signs C.flame screens D.stop-check valves
0ur starboard derrick boom of hatch No.4 is baddly crac...
单项选择题0ur starboard derrick boom of hatch No.4 is baddly cracked（）that it has become entirely useless.
A.at its goose neck to such a extent B.at it's goose neck to such an extent C.at it's goose neck for such a extent D.at its goose neck to such an extent
0vercarring is best prevented by（）.A.assuring heavy car...
单项选择题0vercarring is best prevented by（）.
A.assuring heavy cargo is stowed low in the vessel B.checking the vessel's load line calculations carefully C.inspection of the hold at completion of discharge D.stowing the cargo which is to be discharge last on the bottom
