In the Northern Hemisphere the major ocean currents tend to flow（）.

In some parts of the world there is often a slight fall in tide during the middle of the high water period. The effect is to create a longer period of stand at higher water. This special feature is called a(n)（）.

The apparent wind’s speed can be zero only when two conditions are present. One condition is that the true wind（）.

Advection fog is most commonly caused by（）.

The drift and set of tidal，river，and ocean currents refer to the（）.

In the Northern Hemisphere，your vessel is believed to be in the direct path of a hurricane，and plenty of sea room is available. The best course of action is to bring the wind on the（）.

The direction of the surface wind is（）.

In some river mouths and estuaries the incoming high-tide wave crest overtakes the preceding low-tide trough. This results in a wall of water proceeding upstream，and is called a（）.

Cold water flowing southward through the western part of the Bering Strait between Alaska and Siberia is joined by water circulating counterclockwise in the Bering Sea to form the（）.

The height of a wave is the vertical distance（）.