How does a young dog or cat get to know a new home? The animal uses its nose. Right away it smells its new places. Then it makes wider and wider circles, smelling all the time. Before long it can find its way home very well, even in the dark. It simply follows something it knows well.

    Stories happen about animals who found their way across land they had never smelled before. Take the case of Smoky, a small white cat. Smoky had some funny red hair around its right ear. One day Smoky and his owner began a long journey. They were moving from Oklahoma to Tennessee. When they were just eighteen miles from their Oklahoma home, Smoky jumped out of the car. Then he found his way back to the old house. There he wandered around outside for many days. Finally he disappeared.

    A year later Smoky meowed at the door of a house in Tennessee. A man opened the door. "Is that you, Smoky?" he said in surprise. At first he couldn't believe it. Then he saw the red hair around its right ear. It was Smoky!

    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.

    Trees are one of the oldest " citizens (公民) " of our Earth. They keep our air clean, reduce noise pollution, improve water quality and provide food and building materials.

    Just like us, trees change a lot as they grow. At 1 to 3 years old, young trees learn how to protect themselves. For example, many trees grow thorns( 刺) to warn animals not to go near. Most young trees have large, deep green leaves so that they can catch enough sunlight and change it into their food and energy.

    When trees are 4 years old, they begin to grow very rapidly and become strong enough to face challenges later in life. At the age of 15, trees become young adults. They grow more slowly and begin to produce flowers and fruit.

    It is not until the tree is 20 to 25 years old that it becomes a real adult. The tree reaches its largest size. The adult tree gives us shade, oxygen and natural beauty; it is also a great place for a tree house, or a place for us to read a book, listen to music and so on. If we give the adult tree proper care, it will go on to live healthily for many years.

    Gradually, trees begin to grow older and older and even die. At this time, they still have their important place in nature. When a tree becomes hollow (空心的) or part of it becomes dead, it provides a home to small animals and is a source of food for many other animals.

    In many ways, the life of a tree is similar to our own life experience. When we are looking at the life of a tree, we learn about that each period of life brings its own form of joy and challenge.

    Enjoy every minute of the life of the trees and take care of the trees!

    Are you a big fan of E. T. (Extraterrestrial) or aliens? Then you should read Extraterrestrial Civilizations (《地球以外的文明世界》) by American writer Isaac Asimov (1920~1992). In his 1979 book, Asimov looked at whether there is life beyond the Earth. He also talked about how we might be able to communicate with aliens someday. Asimov even told us that there are possibly about 500, 000 civilizations (文明) in the galaxy(银河系). The book may be a little out of fashion since it came out in the 1970s. But you'll still enjoy the good reasoning (推理 ) and imagination of it. Asimov was a science fiction(科幻故事) master. His most famous works talk about the relationship between robots and humankind.