Tides are created mainly by the pull of the moon on the earth. The moon’s pull causes water in the oceans to be a little deeper

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问题     Tides are created mainly by the pull of the moon on the earth. The moon’s pull causes water in the oceans to be a little deeper at a point closest to the moon and also at a point farthest from the moon, on the opposite side of the earth. These two tidal "waves" follow the apparent movement of the moon around the earth and strike nearly every coast line at intervals of about twelve hours and twenty-five minutes. After reaching a high point, the water level goes down gradually for a little more than six hours and then begins to rise towards a new high point. Hence, most coast lines have two tides a day, and the tides occur fifty minutes later each day. Differences in the coast line and in channels in the ocean bottom may change the time that the tidal wave reaches different points along the same coast line.The difference in water level between high and low tide varies from day to dayaccording to the relative positions of the sun and the moon because the sun also exerts a pull on the earth, although it is only about half as strong as the pull of the moon. When the sun and the moon are pulling along the same line, the tides rise higher, and when they pull at right angles (直角) to one another, the tide is lower. The formation of the coast line and variations in the weather are additional factors which can affect the height of tides. Some sections of the coast are shaped in such a way as to cause much higher tides than in other areas. A strong wind blowing towards the shore may also cause tides to be higher.
The time that high tide occurs at a particular place is affected by all of the following EXCEPT

选项 A、the position of the moon
B、the direction of the wind
C、channels in the sea bottom
D、variations in the coast line

答案B

解析 作者在文章的第3句和第6句中谈到:“这两种潮汐明显是随着月球绕地球的运动而产生,而且几乎每隔12小时25分钟就冲击每条海岸线一次。"作者在文章的结尾部分虽提到强风,但只是说,向海岸吹送的强风也可以提高潮水的水位,并未谈及风向会影响高水位潮汐产生的时间。
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