题目内容：

    Camels are well known for their ability to survive the hot and dry conditions of the desert，but a study suggests they once grew well in colder climates. Scientists have found fossilized（化石） parts of a leg bone belonging to a giant camel that lived in the forests of Canada's High Arctic about 3.5million years ago.

The research is published in the journal Nature Communication. Dr. Mike Buckley, an author of the paper from the university of Manchester, said, "What's special about this story is that this is the northernmost evidence of camels. "The area was warmer than today 3.5 million years ago, but the ancient giant camels would have had to face long and bitter winter, with temperatures below freezing. There would have been snowstorms and about six months of darkness.

While scientists have known for some time that camels existed in North America, with the earliest creatures dating to about 45 million years ago, they were astonished to find a species at such a latitude（纬度).

Over the course of three investigations, which began in 2006，researchers from the Canadian Museum of Nature collected 30 pieces of the leg bone from Ellesmere Island in Canada.

Their size suggested that the animal was about 30% larger than today's camels, measuring about 2.7m from foot to shoulder. Despite its size, the researchers believe it would have been similar in appearance, although it probably had a thicker coat to stay warm.

To investigate further, the team took the protein found in the bone from the fossils and modern animals. Dr. Buckley said, "The results tell us that it is a direct ancestor of modern camels. "

He said the findings provided a new insight into the evolution of this animal. "It suggests that many of the adaptations(适应) that we currently think of, in terms of camels being adapted to warm desert-like environments, could have actually originated through adaptation to quite the opposite cold, bitter environments. Camels 'humps（峰）which store fat could help get through an Arctic six-month winter. Their large eyes would have helped them to see in the low light，and their wide，flat feet would have been just as useful for walking on snow as they are on sand，"he explained.

1.What surprised the scientists when they found the giant camel fossils? ___

A.Their size. B.Their shape.

C.Their place. D.Their number.

2.According to the text, the ancient giant camels___.

A.could date to about 45million years ago

B.struggled to survive in severe conditions

C.were the first ancestors of modern camels

D.lived in an environment without light

3.Compared with modern camels, the ancient giant camels___.

A.were much taller

B.had more humps

C.were slightly stronger

D.had thinner coat

4.We can infer from what Dr. Buckley said that___.

A.giant camels had special adaptations for polar life

B.cold environments prevented giant camels developing

C.the cause of the extinction of giant camels remains unknown

D.the hard climates forced giant camels to adapt to warm environments