单项选择题
The period at high or low tide during which there is no change in the height of the water is called the （）.
A.range of the tide B.plane of the tide C.stand of the tide D.reversing of the tide
单项选择题 The meaning of ebb tide is that （）.
单项选择题 The height of tide is the （）.
单项选择题 The height of eye correction is smaller than geometrical dip because of （）.
