單項(xiàng)選擇題A V-shaped ripple with the point of the V pointing upstream in a river may indicate a（）.

A.submerged rock, not dangerous to navigation
B.sunken wreck, not dangerous to navigation
C.towed-under buoy
D.All of the above


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1.單項(xiàng)選擇題A wet cargo refers to（）.

A.a cargo that will be damaged if it gets wet
B.bulk liquids
C.cargoes that will cause condensation
D.liquids in containers

2.單項(xiàng)選擇題A wildcat ia a（）.

A.deeply-grooved drum on the windlass with sprockets with engage the links of the anchor chain
B.winch that running out of control due to a failure of the overspeed trips
C.line that has jumped off the gypsyhead while under strain
D.nylon line that parts under strain and whips back in a manner

4.單項(xiàng)選擇題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

5.單項(xiàng)選擇題Above-normal tides near the center of a hurricane maybe caused by the（）.

A.high barometric presure
B.jet stream
C.storm surge
D.torrential rains