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58-TPO57-真题-写作-TPO-57 Writing task 1 script

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发表于 2017-7-1 03:05:54 | 显示全部楼层
Reading
Orcas are large predatory whales whose typical coloration is mostly black with some white patches. In recent years, however, sightings of an unusual, almost completely white orca have been reported in the northern Pacific Ocean. One sighting of a white orca occurred near Alaska in 2000. Another sighting of a white orca nicknamed Iceberg by scientists was made off the coast of Russia in 2010.
Because a white orca is so unusual, some scientists have suggested that Iceberg, the whale seen off the coast of Russia, was the same animal as the orca seen earlier near Alaska. However, there are convincing arguments that Iceberg and the Alaskan white orca are actually two different individuals.

Slight Coloration Differences
First, although all the photographs made during the sightings show very light-colored animals, the orca seen in Alaska appears to be just slightly darker than Iceberg. Such differences in coloration suggest that these were two distinct animals that were independently sighted in the northern Pacific.

Sightings Far Apart
Second, the sightings were very far apart. The Alaskan orca was seen near the central Aleutian Islands, a long string of islands that extends westward from the mainland of Alaska. Iceberg was seen near the Commander Islands, off the coast of Russia. More than 1,500 kilometers separate the two locations. Typically, orcas tend to stay near the mainland coast and not travel such long distances.

Age Estimates
Third, when scientists saw the Alaskan white orca in 2000, they estimated that it was around twenty years old, based on the size of its dorsal (back) fin. When researchers saw Iceberg, their estimate of its age, based on the fin size, was also around twenty years but that was in 2010, when the Alaskan orca would have been thirty! The estimates again suggest quite strongly that these are two different individuals.
Listening:
Now listen to part of a lecture on the topic you just read about.
Professor:
Despite what the reading says, it’s perfectly possible that the white orca called iceberg by Russian scientists is in fact the same individual that was spotted earlier near Alaska.
For one thing, the exact color of an orca’s skin can change a bit from season to season. The reason for this is algae. Algae are small plant organisms that grow on whale skin during some parts of the year. Algae growth would make white skin look a bit darker. The Alaskan sighting occurred during a different season than the Russian sighting, so if we take into account the seasonal variation in algae growth, it could have been the same whale seen both times, only one time it was covered with more algae than the other time.
Second, about the distant problem. It’s important to know that orcas live in groups that have different lifestyles. Some groups hunt mammals, while other groups hunt fish. The mammal-eating orcas tend to stay near coastlines and not migrate far, just like the reading say. However, scientists have determined that iceberg belongs to a fish hunting group. Fish-hunting orcas follow migrating fish and can travel over 2,000 kilometers in the open ocean. So it wouldn’t have been unusual for iceberg to travel between Alaska and Russia.
Third, age estimates based on the size of the dorsal fin are not necessarily accurate. You see, after an orca reaches twenty years of age, its dorsal fin doesn’t grow anymore so when scientists see an orca with a fully grown dorsal fin, that orca could be twenty years old, but it could be twenty-five or thirty years old. So, iceberg could easily have been older than the scientists estimated, which means it could have been the same orca as the one seen in Alaska earlier.
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发表于 2017-7-9 09:04:25 | 显示全部楼层
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发表于 2017-8-9 09:29:08 | 显示全部楼层
看到楼主的资料,我就有了信心
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发表于 2017-8-9 09:32:51 | 显示全部楼层
神马都是浮云,资料才是真爱。
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发表于 2017-8-9 09:36:47 | 显示全部楼层
我为资料带盐,我为自己袋盐
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发表于 2017-8-9 09:44:15 | 显示全部楼层
人生有风险,回帖需谨慎,下载资料走人。
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发表于 2017-8-9 09:50:48 | 显示全部楼层
楼主的资料,都惊到我的小伙伴了。
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发表于 2017-8-15 17:27:03 | 显示全部楼层
卧槽,我居然看完了,我竟然下载了。
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发表于 2017-8-22 17:57:37 | 显示全部楼层
资料很好很好 下载来复习 希望可以考到最好的分数
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发表于 2017-8-30 16:07:31 | 显示全部楼层
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i 服了 u!
长江后浪推前浪,
下载资料不手软
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