Once there was an idea that dinosaurs were cold-blooded and only thrived in the swamps and wetlands of tropical climes. But the more we look, the more we realize dinosaurs were found in as many different kinds of habitats as birds and mammals are today. Polar dinosaurs, probably warm-blooded and feathery, were thriving roughly 70- -100 million years ago in great polar forests, of which there is no modem equivalent. Fossils of such dinosaurs have been discovered in Siberia, specifically at the Kakanaut River on the Kamchatka Peninsula. The dinosaur remains found here over the years are mostly teeth, but also include some bones, and they reveal the presence of a variety of species. All of these remains are from the very end of the Cretaceous, 66- 68 million years ago, just before the mass extinction event that saw the extinction of the non-bird dinosaurs. "The material was fragmentary but showed that the Arctic dinosaurs were very diverse," says Pascal Godefroit, an expert on early birds and birdlike dinosaurs who has been involved in the work at the Kakanaut River.

The Kakanaut finds have been important in understanding the end-Cretaceous extinction event. This is in part because Kakanaut was within the Arctic Circle and just 1 ,600 kilometers from the North Pole at that time. Conditions then were warmer than today, but mean annual temperatures were still around 10 degrees Celsius, and there would have been frequent spells below freezing and many months of darkness. Dinosaur fossils found farther east across the Bering Sea in Alaska were left by creatures that endured similar climatic conditions, but some experts have argued that they migrated south in the winter, en masse, to avoid the coldest months. At Kakanaut, researchers found?fragments of eggshell from hadrosaur and theropod dinosaurs,?which suggested that these animals were breeding in polar regions and living there year-round.

Many scientists argue that the dinosaurs went extinct as a result of Earth's collision with a massive asteroid or comet about 66 million years ago that created the Chicxulub Crater on Mexico's Yucatan Peninsula. Other scientists have claimed that falling global temperatures had led to a decline in dinosaurs around the world in the period before the impact (collision). However, the rich fauna (animal life) found by Godefroit and his colleagues suggests that not only had a diverse ecosystem of dinosaurs persisted in the Arctic in the L ate Cretaceous, but also that they were thriving in very cold conditions. The herbivores here must have fed on plants, such as conifers, that remained green year-round and also taken advantage during summer months of a profusion of nutritious fresh growth thrown out by plants bathing in light 24 hours a day.

"For the first time we have firm evidence that these polar dinosaurs were able to reproduce and live in these relatively cold regions. There is no way of knowing for sure, but dinosaurs were probably warm- blooded just like modem birds, which are the direct descendants of dinosaurs," Godefroit told reporters when his findings were published in the German journal Naturwissenschaften in 2009. "The dinosaurs were incredibly diverse in polar regions- as diverse as they were in tropical regions. It was a big surprise for us."

Rather than dinosaurs slowly dying out due to climate change in the period before the impact,?Godefroit believes that the discovery backs up the idea that dinosaurs were killed off in a rapid and brutal fashion by cataclysmic conditions that swept the world following the Chicxulub impact.?▋?Debris in the atmosphere may have blackened the skies for several years, killing off plants and destroying the food supply- -particularly as?large herbivores (plant eaters), such as sauropod dinosaurs, required vast quantities of plant matter to fuel their massive bulk.?▋?Starved for meat, the flesh eaters would eventually have succumbed too, as herbivores disappeared.

▋?It is likely that a combination of factors led to the demise of the non-bird dinosaurs, but the precise explanation remains a fascinating and?enduring?mystery.?▋?It had been thought that Siberia had a paucity of fossils in comparison to its southern neighbors Mongolia and China, but the recent discoveries suggest this may not be true.

para 1:

①Once there was an idea that dinosaurs were cold-blooded and only thrived in the swamps and wetlands of tropical climes. ②But the more we look, the more we realize dinosaurs were found in as many different kinds of habitats as birds and mammals are today. ③Polar dinosaurs, probably warm-blooded and feathery, were thriving roughly 70- -100 million years ago in great polar forests, of which there is no modem equivalent. ④Fossils of such dinosaurs have been discovered in Siberia, specifically at the Kakanaut River on the Kamchatka Peninsula. ⑤The dinosaur remains found here over the years are mostly teeth, but also include some bones, and they reveal the presence of a variety of species. ⑥All of these remains are from the very end of the Cretaceous, 66- 68 million years ago, just before the mass extinction event that saw the extinction of the non-bird dinosaurs. ⑦"The material was fragmentary but showed that the Arctic dinosaurs were very diverse," says Pascal Godefroit, an expert on early birds and birdlike dinosaurs who has been involved in the work at the Kakanaut River.

恐龍化石表明多種溫血極地恐龍的存在；

1. Paragraph 1 indicates which of the following about the habitats of dinosaurs?

A. They were especially suitable for cold-blooded animals.

B.?They were as varied as the habitats of today's animals.

C. They consisted primarily of polar forests, which cannot be found today.

D. They lacked the wetlands and swamps of today's tropical climes.

2. According to paragraph 1, the discoveries at the Kakanaut River site indicate that

A. birdlike dinosaurs evolved around 66-68 million years ago

B. dinosaurs had more teeth and stronger bones than was once thought

C.?before becoming extinct, dinosaurs existed in great diversity in Arctic regions

D. a mass extinction event occurred later than was once thought

3. Which of the following can be inferred about the dinosaur fossils mentioned in paragraph 1 ?

A. They belonged to a number of different periods within the Cretaceous.

B. They were transported along the Kakanaut River from faraway polar forests.

C.?They consisted mostly of disconnected and relatively small parts of animals.

D. They included more remains of birdlike dinosaurs than they did of non-bird dinosaurs.

para 2

①The Kakanaut finds have been important in understanding the end-Cretaceous extinction event. ②This is in part because Kakanaut was within the Arctic Circle and just 1 ,600 kilometers from the North Pole at that time. ③Conditions then were warmer than today, but mean annual temperatures were still around 10 degrees Celsius, and there would have been frequent spells below freezing and many months of darkness. ④Dinosaur fossils found farther east across the Bering Sea in Alaska were left by creatures that endured similar climatic conditions, but some experts have argued that they migrated south in the winter, en masse, to avoid the coldest months. ⑤At Kakanaut, researchers found?fragments of eggshell from hadrosaur and theropod dinosaurs,?which suggested that these animals were breeding in polar regions and living there year-round.

發(fā)現(xiàn)恐龍?jiān)跇O地寒冷區(qū)域生存的證據(jù)；

en masse /??'mɑs/ = all together; in a group

hadrosaur 鴨嘴龍

4. Why does the author provide the information that researchers at Kakanaut found "fragments of eggshell from hadrosaur and theropod dinosaurs"?

A.?To argue against the idea that dinosaurs migrated south to avoid the cold

B. To emphasize that Alaska was warmer than it is today

C. To provide evidence that a mass extinction event took place at the end of the Cretaceous

D. To suggest that climatic conditions could have contributed to the extinction of dinosaurs within the Arctic Circle

5. According to paragraph 2, all of the following were true of Kakanaut at the end of the Cretaceous EXCEPT:

A. It was located quite close to the North Pole.

B.?As compared to the present, conditions there were warmer by about 10 degrees Celsius.

C. Periods of below-freezing temperatures often occurred there.

D. The climate there was similar to Alaska's climate during the same period.

para 3

①M(fèi)any scientists argue that the dinosaurs went extinct as a result of Earth's collision with a massive asteroid or comet about 66 million years ago that created the Chicxulub Crater on Mexico's Yucatan Peninsula. ②Other scientists have claimed that falling global temperatures had led to a decline in dinosaurs around the world in the period before the impact (collision). ③However, the rich fauna (animal life) found by Godefroit and his colleagues suggests that not only had a diverse ecosystem of dinosaurs persisted in the Arctic in the Late Cretaceous, but also that they were thriving in very cold conditions. ④The herbivores here must have fed on plants, such as conifers, that remained green year-round and also taken advantage during summer months of a profusion of nutritious fresh growth thrown out by plants bathing in light 24 hours a day.

寒冷環(huán)境仍然提供了恐龍生存的條件；

6. According to paragraph 3, which of the following was one reason dinosaurs could thrive in the Arctic during the late Cretaceous?

A. Changes in global temperatures following the impact of a massive asteroid or comet in Mexico

B. A diversity of animal life to feed on

C.?The availability of year-round plants and seasonal fresh green growth

D. The possibility for dinosaurs to bathe in light 24 hours a day at certain times of the year

para 4

①"For the first time we have firm evidence that these polar dinosaurs were able to reproduce and live in these relatively cold regions.?②There is no way of knowing for sure, but dinosaurs were probably warm-blooded just like modern?birds, which are the direct descendants of dinosaurs," Godefroit told reporters when his findings were published in the German journal Naturwissenschaften in 2009. ③"The dinosaurs were incredibly diverse in polar regions- as diverse as they were in tropical regions. ④It was a big surprise for us."

G認(rèn)為恐龍?jiān)跇O地區(qū)域曾一度很豐富；

para 5

①Rather than dinosaurs slowly dying out due to climate change in the period before the impact, Godefroit believes that the discovery backs up the idea that dinosaurs were killed off in a rapid and brutal fashion by cataclysmic conditions that swept the world following the Chicxulub impact. ②?▋Debris in the atmosphere may have blackened the skies for several years, killing off plants and destroying the food supply- -particularly as large herbivores (plant eaters), such as sauropod dinosaurs, required vast quantities of plant matter to fuel their massive bulk. ?③?▋Starved for meat, the flesh eaters would eventually have succumbed too, as herbivores disappeared.

恐龍是由于災(zāi)難導(dǎo)致的環(huán)境劇變而滅絕的；

sauropod 蜥腳類(lèi)

7. According to paragraphs 4 and 5, Godefroit's statements about his research findings indicate all of the following EXCEPT:

A.?Warm-blooded and cold-blooded dinosaurs existed in similar numbers across regions.

B. An important similarity probably exists between dinosaurs and modern birds.

C. The findings were unexpected to the researchers themselves.

D. Dinosaurs likely died off quickly after cataclysmic events.

para 6

▋It is likely that a combination of factors led to the demise of the non-bird dinosaurs, but the precise explanation remains a fascinating and?enduring?mystery.?▋?It had been thought that Siberia had a paucity of fossils in comparison to its southern neighbors Mongolia and China, but the recent discoveries suggest this may not be true.

還有待最終確認(rèn)。

8. The word "enduring" in the passage is closest in meaning to

A.?continuing

B. complicated

C. challenging

D. confusing

9. Look at the four squares that indicate where the following sentence could be added to the passage. Where would the sentence best fit? Choose a square to add the sentence to the passage.?

Rather than dinosaurs slowly dying out due to climate change in the period before the impact, Godefroit believes that the discovery backs up the idea that dinosaurs were killed off in a rapid and brutal fashion by cataclysmic conditions that swept the world following the Chicxulub impact.?▋?Debris in the atmosphere may have blackened the skies for several years, killing off plants and destroying the food supply- -particularly as large herbivores (plant eaters), such as sauropod dinosaurs, required vast quantities of plant matter to fuel their massive bulk.?▋?Starved for meat, the flesh eaters would eventually have succumbed too, as herbivores disappeared.

▋?It is likely that a combination of factors led to the demise of the non-bird dinosaurs, but the precise explanation remains a fascinating and?enduring?mystery.?▋?It had been thought that Siberia had a paucity of fossils in comparison to its southern neighbors Mongolia and China, but the recent discoveries suggest this may not be true.

In any case, the research by Godefroit and his team has challenged some long-held assumptions.

?

10. Directions: an introductory sentence for a brief summary of the passage is provided below. Complete the summary by selecting the THREE answer choices that express the most important ideas in the passage. Some sentences do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the passage. This question is worth 2 points.

Dinosaurs used to be present in Siberia and Alaska.

A.?Contrary to what was once thought, polar dinosaurs were probably warm-blooded and thrived in polar forests, where they were as diverse as in tropical regions.

B. Earth was hit by a large object about 66 million years ago, and the debris from the impact may have made the sky black, killing off plants and animals.

C. A German journal, Naturwissenschaften, first published findings that established and confirmed for scientists that modern birds are the direct descendants of polar dinosaurs.

D. The Kamchatka Peninsula in Siberia near the Kakanaut River was the site of research that established the structure of the bones and teeth of non-bird dinosaurs that lived in the region.

E.?Evidence that dinosaurs were able to live in cold climates supports the idea that their extinction was caused by the effects of a massive collision rather than by falling global temperatures.

F. Discoveries from Mongolia and China, where even more dinosaur fossils were found, confirmed the findings from Siberia and provided a basis for comparing fossils from each region.

【BCCAB CAAD ABE】