题目内容：

Polar bears are one of the most popular animals for people. Polar bears are different from every other bear in the world. This is because polar bears have white fur. However, there are many facts about polar bears that people might not be aware of .

The skin of polar bears is black, which according to thinkquest.org  allows them to absorb more heat from the sun. Polar bear fur is transparent , because it is made up of hollow guard hairs. Loc.gov explains that the reason polar bears display white fur is that when the sun hits the fur ,the hollow spaces in the hair scatter the light. Since none of the light is absorbed, the light reflected back appears white to human eyes.

Polar bears’ conservation status is considered close to extinction. Global warming is considered the main cause of the decline in polar population. Polar bears use ice floats to hunt for their food. However, these ice floats are melting so polar bears are starting to drown in the search for food ,and the food is becoming more difficult to get. Contrary to popular belief, polar bears do not eat penguins ,because polar bears are not found in the Antarctic region of the world. Polar bears are only found around the Arctic Circle. Polar bears do not drink water. They get all the water they need from the prey they eat.

FES. Gov specifies that polar bears are considered the largest land carnivores(食肉动物) in the world. The polar bear weight ranges between 700--1,500 pounds. Since the polar bear habitat is melting away, their main evolutionary advantages are fading. Polar bears are not able to use their camouflage(伪装) to find prey in habitats not covered with snow. Polar bears do not hibernate(冬眠). However, when the weather gets uncomfortable, or mothers give birth, polar bears will dig themselves a hidden home.

What can we do to help save the polar bears? We can donate to organizations like the World Wildlife Fund, reduce our carbon footprint, and send letters to politicians explaining to them that we need to set up more preserves to help save the polar bear habitat.

1.What do we know about the fur of the polar bears?

A. It absorbs more heat from the sun.

B. It is black and hollow.

C. Light can pass through it.

D. It is white actually.

2.What does “main evolutionary advantages” in Paragraph 4 refer  to？

A. Hibernation habit    B. The function of their fur

C. Eating meat    D. Their weight

3.What do we know from the passage?

A. Polar bears face danger due to the melting of ice floats.

B. The biggest polar bears weigh about 1,000 pounds.

C. Polar bears never hibernate and do not need water.

D. Polar bears are the largest carnivores in the world.

4.Which of the following ways is NOT the measure used to protect polar bears according to the passage?

A. Donating to wildlife conservation organizations.

B. Trying our best to reduce greenhouse gases.

C. Writing letters to make people protect polar bears.

D. Setting up more polar bear conservation organizations.