单项选择题
The velocity of the wind，its steady direction，and the amount of time it has blown determines a wind driven current’s（）.
A.temperature B.density C.deflection D.speed
单项选择题 When crossing a front,isobars tend to（）.
单项选择题 Details of coast radio stations and radar stations can be found in（）.
单项选择题 A current perpendicular to a vessel’s track has the greatest effect on the vessel’s course made good（）.
