GWD - CR - 大全 附解释(23)

seeks to provide support. C. The first is a position that the reasoning contends is inadequately supported by the evidence; the second is a

position for which the reasoning seeks to provide support. D. The first is a position that the reasoning contends is inadequately supported by the evidence; the second is evidence

used to support the reasoning‘s contention. E. The first is a position that the reasoning contends is inadequately supported by the evidence; the second is evidence

that has been used to support that position. ------------------------------------------------------------------------------------------------------- 22. GWD27-Q22:

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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.

原文没有说明5000万年后的鲸鱼是否只喝淡水，只说到可以喝海水；B属于无关选项。 虽然这题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.

6000万年前到5000万年前的鲸鱼化石不会在那个时期被宽阔海洋从古亚洲分离出去的大陆上发现。

大家的理解是鲸鱼不可能游过海洋，因为没法过滤海水中的盐分；但是，其实原文就有说是从湖泊和河流进化来的，那么分离出去的大陆也是有可能有湖泊和河流，也有可能恰好这些湖泊和河流都有古鲸鱼，那么就有发现化石的可能；所以A也有些不充分，但却是最好的选项。

只喝淡水的鲸鱼可以到海里，但是要回去淡水里喝水，所以就不可以在海里呆太久。 因为鲸鱼是在asia起源的，所以在他们能靠海水生活之前，他们不可能出现在其他和asia被海隔开的大州上，游不过去嘛，会干死的。A中就给出了这个信息。

------------------------------------------------------------------------------------------------ 28: GWD-29-Q9

Manatees, aquatic mammals inhabiting Florida‘s rivers and coastal waters, swim close to the surface and are frequently killed in collisions with boats. To address the problem, boat traffic in manatee-populated waters is being required to maintain very low speeds. Unfortunately, manatees are unable to hear low-pitched sounds and a boat‘s sound lowers in pitch as the boat slows. Therefore, this approach may in fact make things worse rather than better. Which of the following, if true, casts most doubt on the conclusion?

A. The areas where boats would have to maintain low speeds were decided partly on the basis of manatee-population

estimates and partly from numbers of reported collisions between manatees and boats. B. Because the water hyacinth that manatees feed on grows best in water that is nearly still, water hyacinth beds can

be disturbed or damaged by fast-moving boat traffic. C. Over the last several decades, boat traffic in Florida‘s coastal waters has been increasing almost continuously and

now represents the greatest threat to the endangered manatee population. D. The sound of a boat engine generally travels much further under water than it does through the air.

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