Question

    Meet the longest-living vertebrate（脊椎动物）in the world, the Greenland shark.

Found primarily in the very cold waters of the North Atlantic, these slow-swimming sharks can be as big as the largest great whites, reaching up to 21 feet in length. They're among the largest of carnivorous（食肉的）fish, and yet grow perhaps only a centimeter or so a year. Such slow growth yet big size is usually an indicator of a long-lived animal.

“We only expected that the sharks might be very old,” Julius Nielsen, at the University of Copenhagen in Denmark, told NPR in 2016. “But we did not know in advance. And it was, of course, a very big surprise to learn that it was actually the oldest vertebrate animal.”

Imagine being 150 years old before you're ready to have your first child! Imagine being born before the United States was even a reality. For humans-who rarely make it to a century mark—it's difficult to fully understand.

Little is known about Greenland sharks, even basics such as where they give birth or how many of them there are, though researchers at a July 2017 conference at the University of Exeter thought that they may mate in “hidden” Arctic fjords. No one has even witnessed one hunting, though they have been found to have various vertebrate ones in their stomachs such as polar bear, seals, fast-swimming fish and even moose etc.

Given the shark's incredibly long lifespans, scientists are diving into the sea creature's genome, looking for clues. That conference also highlighted the work being done to separate the shark's longevity gene, with complete DNA information gathered from almost 100 sharks, including some born in the 1750s. Finding such a gene could go a long way in explaining why some vertebrates, like humans, have such limited lifespans.

These sharks also serve as swimming history books. Their tissue, bones and DNA could tell us a great deal about the waters of the world from a time before the Industrial Revolution, large-scale commercial fishing and the pronounced ocean pollution we see today.

Check out what it's like to swim with one in this encounter with what is a small and young—and yet to us, still fairly old—Greenland shark.

1.What can we know about Greenland sharks from the first two paragraphs?

A.Longest-living, and slow-swimming carnivorous vertebrate.

B.Longest-living, and slowest-swimming vertebrate.

C.Largest, but fast-growing carnivorous vertebrate.

D.Longest-living, largest carnivorous vertebrate but fast-growing.

2.Why were scientists surprised after they examined Greenland shark?

A.Greenland shark can live as old as humans.

B.Greenland shark is the largest animal in the world.

C.Greenland shark can live more than one hundred years.

D.Greenland shark is really the oldest vertebrate in the world.

3.What kind of animals do Greenland sharks prefer?

A.Both polar bear and seal. B.Only fast-swimming fish.

C.Various vertebrate animals. D.Polar bear, moose and fish.

4.What information can we get from the passage?

A.Scientists declare that they have known all about Greenland sharks.

B.Scientists want to get more information from their study on sharks.

C.Scientists consider sharks can only serve as swimming history books.

D.Scientists just want to know why Greenland sharks have a long life.

Answer

1.A

2.D

3.C

4.B

【解析】

这是一篇说明文。科学家们发现格陵兰鲨是世界上最长寿的脊椎动物。

1.细节理解题。根据第一段中的“Meet the longest-living vertebrate（脊椎动物）in the world, the Greenland shark.”可知格陵兰鲨鱼是世界上最长寿的脊椎动物。根据第二段中的“these slow-swimming sharks can be as big as the largest great whites, reaching up to 21 feet in length. They're among the largest of carnivorous（食肉的）fish, and yet grow perhaps only a centimeter or so a year.”可知这种缓慢游动的鲨鱼主要生活在北大西洋的寒冷水域，体型可与最大的大白鲨一样大，身长可达21英尺。它们是最大的肉食性鱼类之一，但可能一年只长一厘米左右。综合可知这种鲨鱼是最长寿的（longest），行动缓慢的(slow-moving),生长缓慢的（slow-growing）,故选A项。

2.细节理解题。根据第三段中的““We only expected that the sharks might be very old,”和“But we did not know in advance. And it was, of course, a very big surprise to learn that it was actually the oldest vertebrate animal.”可知这些科学家认为鲨鱼可能很老，但他们得知它真的是最古老的脊椎动物时，他们非常惊讶。也就是说科学家们因为发现格陵兰鲨鱼真的是世界上最古老的脊椎动物而感到惊讶。故选D项。

3.细节理解题。根据第五段中的“No one has even witnessed one hunting, though they have been found to have various vertebrate ones in their stomachs such as polar bear, seals, fast-swimming fish and even moose etc. ”可知甚至没有人见过格陵兰鲨鱼捕猎，但人们发现他们的胃里有各种各样的脊椎动物，如北极熊、海豹、快速游动的鱼，甚至还有驼鹿等。由此可知，格陵兰鲨鱼喜欢吃各种各样的脊椎动物。故选C项。

4.推理判断题。根据第六段 “Given the shark's incredibly long lifespans, scientists are diving into the sea creature's genome, looking for clues. …Finding such a gene could go a long way in explaining why some vertebrates, like humans, have such limited lifespans.”可知考虑到这种鲨鱼令人难以置信的长寿，科学家们正在深入研究这种海洋生物的基因组，寻找线索。那次会议还强调了分离鲨鱼长寿基因的工作，（他们）从近100只鲨鱼中收集了完整的DNA信息，其中包括一些出生在18世纪50年代的鲨鱼。找到这样的基因有助于解释为什么像人类这样的脊椎动物寿命如此有限。由此推断科学家们希望从他们对鲨鱼的研究中获得更多关于长寿的信息。故选B项。