The author gives substance to the passag-考呗网题库移动版

单选题The author gives substance to the passage through the use of

A．interviews with authorities in the field of water controls
B．opinion and personal observations
C．definitions which clarify important terms
D．strong argument and persuasion

参考答案B

解析:【答案】B。解析：通过浏览整篇=文章以及对段落首末句的分析可知，作者是在发表自己的个人观点并分层次具体阐述，所以B项正确。

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单选题The phrase“prior o”(Pata．2)probably means______

A．after
B．during
C．before
D．beyond

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单选题根据以下材料，回答题
When we analyze the salt salinity(盐浓度)of oceanwaters，we find that it varies only slightlyfrom place to place．Nevertheless，some of these small changes are important．There are three basic processes that cause a change in oceanicsalinity．One of these is the subtraction of water from theoceajl bv means of evaporation．In this manner，the salinity is increased，since the salt stays be—hind．If this is carried to the extreme，of course，white salt would be left behind；this，by the way．is how much of the table salt we use is actually obtained．
The opposite of evaporation is precipitation，such as rain，by which water is added to theo—cean．Here the ocean is being diluted so that the salinity is decreased．This may occur in areas ofhigh rainfall or in coastal regions where rivers flow into the ocean．Thus salinity may be increased bythe subtraction of water by evaporation，or decreased by the addition of fresh water by precipitation．
Normally than it is in in hot regions where the sun is very stron9，the ocean salinity is somewhat higherparts of the world where there is not as much evaporation．Similarly，in coastalregions where rivers dilute the sea．salinity is somewhat lower than in other oceanic areas A third process by which salinity may be altered is associated with the formation and melting of sea ice．When seawater is frozen，the dissolved materials are left behind．In this manner，seawaterdirectly beneath freshly formed sea ice has a higher salinity than it did before the ice appeared．Of course，when this ice melts，it will tend to decrease the salinity of the surrounding water．In the Weddell Sea，the densest water in the ocean is formed as a result of this
freezing pro—cess, which increases the salinity of cold water. This heavy water sinks and is found in the deeper portion of the oceans of the world. ______
This passage mainly tells us about

A． the analysis of the salinity of ocean waters
B． the causes of the variation in oceanic salinity
C． the importance of the changes in oceanic salinity
D． the different forms of salts in ocean waters

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单选题 It can be known from the passage that increase in the salinity of ocean water is caused by______

A． melting of sea ice
B． precipitation
C． evaporation
D． supplement of salt

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