Question

As the world's largest terrestrial carnivore (陆地食肉动物), the polar bear is the king of the great white north.Adult males can measure more than 9 feet in length and weigh between 770 and 1,430 pounds.The polar bear has a strong body while their heads are narrow with small, rounded ears.

Polar bears can be found in northern Canada, Greenland, Norway and Russia, and there have been reports that polar bear tracks have been found as far north as the North Pole.The 5,000,000－square－mile range of the polar bear circles the Arctic and contains pieces of open water where seals are easily caught.

Polar bears live on the annual Arctic sea ice that provides a platform from which they can hunt.They hunt seals on the sea ice by breaking into seal dens in the sea ice.The dens aren't visible from above, but seeing is less important than smelling to polar bears—with their sharp sense of smell, polar bears can sense the breathing holes of seals in their dens beneath the snow and ice.As the southern edge of the Arctic ice cap melts in summer, polar bears are forced to stay on land and spend their summers fasting (禁食), living off body fat stored from hunting in spring and winter.

With about 22,000 polar bears living in the wild, the species is not endangered at the moment, but its future is far from certain.Climate change is causing the disappearance of sea ice from which polar bears hunt seals.Sea ice in the Arctic is melting earlier and forming later each year.People have reached an agreement that controls the hunting of polar bears and directs each nation to protect their habitats, but it does not protect the bears against the biggest man－made threat to their survival:  global warming.If current warming trends continue, scientists believe that polar bears may disappear within 100 years.

1.Polar bears search for seals mainly through their ____.

A. eyes    B. ears

C. noses    D. necks

2.The underlined word “dens” in paragraph 3 most probably means “____”．

A. the skin of the wild animals

B. the home of wild animals

C. the breathing holes of seals

D. water of the deep sea

3.Which of the following statements is TRUE？

A. A polar bear measures at least 9 feet long.

B. Polar bears can be found in both the North Pole and the South Pole.

C. Polar bears stop hunting in summer because seals are hidden at that time.

D. Polar bears may die out as a result of climate change.

Answer

1.C

2.B

3.D

【解析】

本文是一篇说明文。主要介绍北极熊是如何捕食的，但由于全球气候变化，北极熊面临着灭绝的危险。

1.细节理解题。根据第三段中的..but seeing is less important than smelling to polar bears—with their sharp sense of smell...可知，北极熊主要依靠它们敏锐的嗅觉来寻找食物。故选C项。

2.词义猜测题。根据后文中的polar bears can sense the breathing holes of seals in their dens beneath the snow and ice.可知，北极熊能通过嗅觉感知到冰雪下面在自己家里吃海豹的呼吸空，所以dens指野生动物的家。故选B项。

3.推理判断题。根据文章最后一段中的Climate change is causing the disappearance of sea ice from which polar bears hunt seals...but it does not protect...global warming...scientists believe that polar bears may disappear within 100 years.可知，气候的变化可能会导致北极熊的灭绝。故选D项。