单项选择题
The set of the ocean current is caused by（）.
A.density differences of the water B.rotation of the earth C.direction of primary circulation of air D.all of the above
单项选择题 The set of the equatorial countercurrent is generally to the（）.
单项选择题 The set of the current is the（）.
单项选择题 The north equatorial current flows to the（）.
