标题: 紧急求助一道CR，谢谢NN们，还有3天就考试 [打印本页] 作者: Cherliuiking 时间: 2010-1-30 14:41 标题: 紧急求助一道CR，谢谢NN们，还有3天就考试 Whales originated in the freshwater lakes and rivers of ancient Asia about sixty million years ago. Not until about ten million years later did species of whales develop specialized kidneys enabling them to drink salt water. Although fossil evidence shows that some early whale species that lacked such kidneys sometimes swam in the Earth’s saltwater oceans, these species must have had to return frequently to freshwater rivers to drink.
Which of the following is most strongly supported by the information given?
Fossils of whale species dating from between sixty million and fifty million years ago will not be found on continents that were at the time separated from ancient Asia by wide expanses of ocean. Among whale fossils that date from later than about fifty million years ago, none are fossils of whale species that drank only fresh water. Fossils of whale species that drank fresh water will not be found in close proximity to fossils of whale species that drank salt water. The earliest whales that drank salt water differed from fresh-water-drinking whales only in their possession of specialized kidneys. Between sixty million and fifty million years ago, the freshwater lakes and rivers in which whales originated were gradually invaded by salt water. A我能明白，但是B有什么问题呢？xiexie作者: pammy0926 时间: 2010-1-30 16:36
。。。我看了题目就选了D。。。 牛人们请来帮助一下。。。作者: girlwithwings 时间: 2010-1-31 15:35
D 对吗？ 我也选D。 说明原因独一无二是充分条件，所以支持文中原因可以推出结论。作者: Cherliuiking 时间: 2010-2-1 12:04
貌似D不对吧，因为文中没提到是不是仅仅是肾脏一样的哦作者: pammy0926 时间: 2010-2-2 12:03 标题: 请教了以后。。。 请教了一个native speaker,他说是：Answer is A -- because whales from Asian freshwater lakes couldn't go far in salt water. Ocean water is salt water. Therefore, they couldn't get to conitnents far from Asia.