蓝皮P34-89，大全没有

rock19840717

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?

A)    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.

B)     Among whale fossils that date from later than about fifty million years ago, none are fossils of whale species that drank only fresh water

C)    Fossils of whale species that drank fresh water will not be found in close proximity to fossils of whale species that drank salt water

D)    The earliest whales that drank salt water differed from fresh-water-drinking whales only in their possession of specialized kidneys.

E)     Between sixty million and fifty million years ago, the freshwater lakes and rivers in which whales originated were gradually invaded by salt water.

我当时选D，觉得是排除他因，所有的都想同，仅仅是因为肾不同，不就能说明原文结论these species must have had to return frequently to freshwater rivers to drink了吗，不知道哪里不对，请教大家

rnir

A是直接可以从原文推断出来的，1000万年以前的鲸都可能是淡水鲸，更早的鲸就更不可能通过海水游到其它大陆去
D最大的缺陷我觉得是那个Only，原文并没有说在咸水鲸和淡水鲸具体有那些区别

rock19840717

恩，很简单，没错没错，谢谢LS