Noise pollution is doing much harm to our health now. Noise, in fact, is unwanted sound and is a kind of invisible (无形的) killer. More and more students enjoy listening to music very much. When they listen to MP3 players, they like to turn up the volume (音量). Some people love listening to loud music. Furthermore, while watching TV, they keep the volume up. But they haven't realized that the noise is weakening their hearing. In fact, the noise not only influences each member in the family, but also makes a difference to the comfort of neighbors.

Noise pollution is a source of increasing misery (痛苦) to people in our society. If people are often disturbed by it, they may feel uncomfortable or upset. What's worse, the noise can make people mad sometimes. If a worker works in a printing factory for too long, his/her hearing loss is much faster than a common person working in a quieter environment. So everybody must pay more attention to noise pollution. Generally speaking, the following four types of noise should be watched out for:

    ◆Noise in the street

    ◆Construction site (建筑工地) noise

    ◆Noise at work

    ◆Transportation noise

    I think the local department (部门) should take measures to control the noise levels, but it's everybody's duty to keep a quiet environment.

    The polar bear is a very big white bear. We call it the polar bear because it lives in the Arctic Circle（北极圈） near the North Pole.

    The polar bear lives in snow and ice. At the North Pole there is only snow, ice and water. There is not any land. The polar bear has a very warm coat because the weather is cold in Arctic Circle. You can't find the polar bear easily in the snow because its coat is white.

    A grown-up polar bear is usually about three meters long and weights about 450 kilos. It can stand up on its back legs because it has very wide feet. It can use its front legs like arms. The polar bear can swim very well. It catches fish and sea animals for food. It goes into the sea when it is afraid. People kill the polar bear for its beautiful white coat. The governments of Canada and United States call on that people should stop killing polar bears. They don't want these beautiful animals to die out.

根据短文内容回答问题。

    Our eyes may be playing tricks on us.  New research shows that sometimes people physically see what they want to see. Cornell University social psychologist(心理学家) David

    Dunning carried out experiments to test whether wishful thinking can actually affect what we see.

    “It's well proved from what is experienced in everyday life, and from the laboratory as well, that people think what they want to think," he says. "We're taking this a step further.

    We're asking if strong wishes and fears can actually affect what people physically see."

    Dunning and his assistants told volunteers that a computer game would show them either a letter or number to decide whether they would drink orange juice or fruit syrup(果子露).

    As they wrote in the Journal of Personality and Social Psychology, the computer would flash an ambiguous picture, which could be seen as the letter "B" or the number "13". Volunteers who were told that a letter would get them orange juice most often reported seeing "B". Those who were told that a number would get them orange juice most often saw "13".

    The researchers also used a hidden camera to track volunteers' eye movements, particularly the first eye movement. "We don't control them," Dunning says, "and they don't even know that we are watching them, so it honestly shows what a person is seeing."

    "This research suggests that the brain is doing a lot of work between the eye and the conscious awareness to affect what we think," Dunning concludes (得出结论). "Before we even see the world, our brain has decided to keep what we want to see and avoid what we don't want to see."

    Some of the greatest problems we face today are the destruction (破坏) of our environment. Brown clouds, polluted water, endangered wild animals…. these problems seem so huge.

    So my family does what we can. We take cloth bags to stores instead of using plastic bags. We walk where we don't have to drive…

    But does it do any good? When I am the only one in line at the market with cloth bags, am I doing any good? Does my walking to stores make any real difference to the world?

    I recently learned something about flamingos(火烈鸟) which like to get together in groups of a thousand or more. Every year, when the time comes for migration(迁徙), a few of them first take off from the lake. But none of the others seem to notice. So the small group returns. However, the next day they try again. This time a few more fly along with them, but most of them still pay no attention, so they return again. They try for several times. Every time a few more birds join in but, since thousands of the others still take no notice, the great migration plan is once more stopped.

    Then one day something changes. The same small group of birds once again starts flying and a small number more join in just as before, then more. Finally, they all take flight and the migration really begins. What a spectacular sight it must be — thousands of flamingos taking off into the sky at once!

    A few can make a difference. Even if you're the one to take the first step, and continue trying, others will someday take notice and together we will solve even our greatest problems.