2017年職稱英語《衛(wèi)生類B級》備考閱讀判斷題2

更新時間：2016-12-26 14:04:23 來源：環(huán)球青藤

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摘要　　【摘要】目前備考2017年職稱英語考試的考生在循序漸進的模擬中。環(huán)球網(wǎng)校為考生整理了2017年職稱英語《衛(wèi)生類B級》備考閱讀判斷題2，希望備考2017年職稱英語考試的考生都能順利通關(guān)，更多資料敬請關(guān)注網(wǎng)校職

　　【摘要】目前備考2017年職稱英語考試的考生在循序漸進的模擬中。環(huán)球網(wǎng)校為考生整理了“2017年職稱英語《衛(wèi)生類B級》備考閱讀判斷題2”，希望備考2017年職稱英語考試的考生都能順利通關(guān)，更多資料敬請關(guān)注網(wǎng)校職稱英語考試頻道……

　　相關(guān)推薦：2017年職稱英語考試綜合類補全短文練習匯總　　

　　Where Has the Salt Come from?

　　Every now and then, we meet a fact about our earth that makes us feel strange and no answer for the fact has yet been found. Such a fact is the existence of salt in the oceans. How did it get there?

　　We simply do not know how the salt got into the ocean! We do know, of course, that salt is water-soluble, and so passes into the oceans with rainwater. The salt of the earth's surface is constantly being dissolved (溶解) and is passing into the ocean.

　　But we do not know whether this can explain the huge quantity of salt in oceans, if all the oceans were dried up, enough salt would be left to build a wall 180 miles high and a mile thick. Such a wall would reach once around the world at the Equator (赤道)!

　　The common salt that we all use is produced from seawater or the water of salt lakes, from salt springs (源泉) and from deposits of rock salt. The concentration (濃度) of salt in seawater ranges from about three per cent to three-and-one-half percent. The Dead Sea, which covers an area of about 340 square miles, contains about 11,600,000,000 tons of salt!

　　On the average, a gallon (加侖) of seawater contains about a quarter of a pound of salt. The beds of rock salt that are found in various parts of the world were all originally formed by the evaporation (蒸發(fā)) of seawater millions of years ago. It is believed that the thick rock-salt deposits were formed after about nine-tenth of the volume of seawater had been evaporated.

　　Most commercial salt is obtained from rock salt. The usual method is to drill wells (井) down to the salt beds. Pure "water is pumped down (抽進去) through a pipe. The water dissolves the salt and it is forced through another pipe up to the surface.

　　16 We have not fully understood how salt got into the ocean.