单项选择题
A.on course B.headed fair C.holding on D.in shape
A tow of 9 barges is made up three abreast by three lon...
单项选择题A tow of 9 barges is made up three abreast by three long. The towboat is faced up to the last barge of the center string. The outer two strings of barges are the（）.
A.port and starboard strings B.outer strings C.drag strings D.side strings
A tow can override its tug as a result of（）.A.a mechani...
单项选择题A tow can override its tug as a result of（）.
A.a mechanical breakdown on the tug B.adverse tidal current conditions C.the tug reducing its speed D.All of the above
A time diagram is a diagram on the plane of the（）.A.cel...
单项选择题A time diagram is a diagram on the plane of the（）.
A.celestial meridian B.celestial equator C.celestial horizon D.principal vertical circle
