单项选择题
In mid-ocean，the characteristics of a wave are determined by three factors. What is NOT one of these factors?（）
A.Effect of the moon's gravity B.Fetch C.Wind velocity D.Length of time a wind has been blowing
单项选择题 Generally speaking，a ship steaming across the North Pacific from Japan to Seattle is likely to experience（）.
单项选择题 Currents are（）in rate and direction.
单项选择题 Current refers to the（）.
