单项选择题
Stand of the tide is that time when（）.
A.the vertical rise or fall of the tide has stopped B.slack water occurs C.tidal current is at a maximum D.the actual depth of the water equals the charted depth
单项选择题 Spring tides are tides that（）.
单项选择题 River currents tend to（）.
单项选择题 Priming of the tides occurs（）.
