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标题: GWD-27-22再问一题！ [打印本页]
作者: rainbooow 时间: 2007-4-21 21:48
标题: GWD-27-22再问一题！
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
答案选A，如何理解？
[此贴子已经被作者于2007-4-21 21:48:40编辑过]
作者: pangpangshin 时间: 2007-4-22 22:29
我也很疑惑这个题目 希望有NN来解答
作者: gonghao 时间: 2007-4-24 14:33
whales 6亿年前在亚洲上出现,5亿年前会喝咸水
A说不可能在被很大很大一片海隔开的远离亚洲的大陆上找到5亿到6亿年间的whales样本.
因为:1.whale是在亚大陆上出现的.2.另外一片大陆远离亚洲,并且有很大的水隔开,这样一来虽然whale可能没有kid但可以在咸水里游,但还是要回到淡水里,对于wide expanses of ocean来说,whales不能克服必须再回亚洲的淡水里去.
作者: ly365 时间: 2007-5-19 12:27
the answer is b
作者: ly365 时间: 2007-5-19 13:05
E也不对，鲸鱼不一定是没有淡水了才喝海水的呀，有可能是想出去逛逛呢，不得不喝海水。
作者: andylouis 时间: 2007-9-13 21:14
UP
作者: 水里游 时间: 2008-10-9 20:06
gonghao解释得真好~
作者: skigorush 时间: 2009-7-29 20:59
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