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（）.

In some parts of the world there is often a slight fall...

单项选择题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)（）.

In shallow water，waves that are too steep to be stable，...

单项选择题In shallow water，waves that are too steep to be stable，causing the crests to move forward faster than the rest of the wave，are called（）.

In most cases，the direction of the apparent wind lies b...

单项选择题In most cases，the direction of the apparent wind lies between the bow and（）.