单项选择题
A.heavy rain within six hours B.a decrease in wind velocity C.a change in the present weather conditions D.that fog will soon set in
A radar range to a small，charted object such as a light...
单项选择题A radar range to a small，charted object such as a light will provide a line of position in which form? （）
A.Straight line B.Arc C.Parabola D.Hyperbola
A quick and rapid motion of a ship in a seaway is an in...
单项选择题A quick and rapid motion of a ship in a seaway is an indication of a(n) （）.
A.large GM B.high center of gravity C.excessive free surface D.small GZ
A pumproom is suspected of accumulating gases after a v...
单项选择题A pumproom is suspected of accumulating gases after a ventilation machinery breakdown. Where should the combustible gas indicator case be placed when testing the pumproom atmosphere for combustible gases? （）
A.In the lower level of the pumproom B.In the middle level of the pumproom C.In the upper level of the pumproom D.On the deck outside the pumproom
