The velocity of the wind，its steady direction，and the amount of time it has blown determines a wind driven current’s（）.

A.change from smooth curves within the air mass to sharp bends at the front
B.change from sharp bends within the air mass to smooth curves at the front
C.pass smoothly across the front with no change
D.become closer together at the front and pass through in straight lines

A.Admiralty Chart
B.Admiralty Light list
C.Admiralty List of Radio Signals
D.Admiralty Notices to Mariners

A.at high vessel speeds
B.at low vessel speeds
C.in shallow water
D.in deep water