Gasoline (汽油) prices are getting higher and higher. The prices make it hard for drivers to afford the fuel. One group held a special event to display（展示）new kinds of cars .The new cars are different and they can run on many different kinds of fuels.

Some of these cars are called hybrids(混合动力). They can run on different kinds of fuels. One kind of them runs on a special fuel cell which is filled with a gas called hydrogen.

      The fuel cell cars are also better in another way. They give off no emissions（排放物）. They are very clean, and don't give off bad fumes when they are running.

One man who makes fuel cell cars is excited about the hydrogen fuel cell technology. He says we will never run out of the sources of the fuel, but we may run out of the oil. Once we use oil up, it will take millions of years for more oil to form. Since gasoline is made from oil, that could be a problem for companies that make traditional cars, and for drives. However, it won't be a problem for cars that run on fuel cells.

      Buses that run on hydrogen fuel cell power are being tested on the road. They could become a common form of transportation in the near future

    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!

How honey is made

    Different weather makes people feel different. It influences health, intelligence(智力) and feelings.

    In August, is very hot and wet in the southern part of the United States, People there have heart trouble and other kinds of health problems during this month. In the Northeast and the Middle West, it is very hot at some times and very cold at other times. People in these states have more heart trouble after the weather changes in February or March.

    The weather can also influence intelligence. For example, in a scientific report, IQ (智商) of a group of students was very high when a very strong wind came, but after the strong wind, their IQ was 10% below. The wind can help people have more intelligence. Very hot weather, on the other hand, can make it lower. Students in many schools of the United States often get worse on exams in the hot months of the year (July and August).

    Weather also has a strong influence on people's feelings. Winter may be a bad time for thin people. They usually feel cold during these months. They might feel unhappy during cold weather. But fat people may have a hard time in hot summer. At about 18℃, people become stronger.

    Low air pressure may make people forgetful. People leave more bags on buses and in shops on low-pressure days. There is a "good weather" for health. People feel best at a temperature of about 18℃.

    Are you feeling sad, tired, forgetful, or unhappy may be the weather's problem today?

    Man has a big brain(脑). He can think, learn and speak. Scientists always say that men are different from animals because they can think and learn. They know now that dogs, rats, birds can learn too. They are beginning to understand that men are different from animals because they can speak. Animals cannot speak. They make noises when they are afraid, or angry or unhappy. Apes(类人猿) can understand some things more quickly than humans. One or two of them can learn a few words. But they cannot join words to make sentences. They cannot think like us because they have no language(语言). They can never think about the future. Language is a wonderful thing. Man can build a modern world because he has language. Every child can speak his own language very well when he is four or five, but no animals learn to speak. How do children learn it? Scientists do not really know. What happens inside our body when we speak? They do not know. They only know that man can speak because he has a brain.