Monarch butterflies from eastern Canada make the most amazing journey in the insect world. Each year, this butterfly travels about 3000miles to its winter home in central Mexico(墨西哥). How can it fly so far? And why does it make this long and dangerous trip? Scientists still don't have an answer.

 For many years, people in Mexico wondered where the orange-and-black butterflies came from every winter. Then, in 1937, a scientist started to follow and study the butterflies. For the next 20 years, he discovered that one butterfly started its journey in Canada. Four months later, it arrived in Mexico.

 The length of the butterflies find their way back to the same place? Another amazing thing is that the butterflies always return to the same area in central Mexico.

 How do the butterflies find their way back to the same place? This is an interesting question because only every fourth generation(代) makes the trip south. In other words, the butterfly that travels to Mexico this year is the great-great-grandchild of the butterfly that traveled there last year.

 Each year, four generations of a Monarch butterfly family are born. Each generation of the family has a very different life. The first generation is born in the south in late April. It slowly moves north, reproduces(繁衍), and then dies. On the trip north,two more generations are born, reproduce, and die. Each of these generations of butterflies is born. This generation has a much longer life. It lives for about eight months. This generation of butterflies makes the amazing journey back to the winter home of its great-great-grandparents. The butterflies spend the winter there, and in the spring they reproduce and then die. Their offspring will be the first generation of the next circle of life.

 Today, people are still studying the Monarch butterfly. But they are not clear about everything.

    Here is a page from a magazine called Future. Read the following information about things that may happen in ten years.

    Cars will run on solar power (太阳能) and will be much cleaner. They will be much safer. For example, if you are too close to another car or if you are driving dangerously, your car will slow down or stop by itself.
    New cities will have to be built in the sea. Some cities on water will have two levels (层). People will live on the upper level; the lower level will be used for traffic, shops and factories.
    Biotechnology (生物技术) will make food better and healthier. Plants without insects or illnesses (病虫害) will be developed. The taste of fruit and vegetables will be better and food will be kept longer.
    Many new ways to cure (治愈) illnesses will be found. People will use products of genetic engineering (基因产品) to cure more illnesses. However, some new illnesses will appear.

    Radios, telephones and televisions are widely used in the world. When you switch on the radio, you can listen. But when you use the telephone, not only can you listen to others, but also you can chat with them. However, you cannot see anything at all. Television is much better than both of them. People can watch TV and listen to it, but they cannot take part in what they see.

    Today, some people are using a new type of telephone called vision phone. With it two people who are talking can see each other. Vision phones can be of great use when you have something to show the person whom you are calling. It may also have other uses in the future. Some day you may be able to call up a library and ask to read a book right over your vision phone. You may be able to do the shopping through it too. Perhaps in the near future, vision phones will come into our everyday life.

    Can dolphins (海豚) talk? Maybe they cannot talk with words, but they can talk with sounds. They show their feelings with sounds. Dolphins travel in a group. We call a group of fish a "school". They do not study, but they travel together. Dolphins are mammals (哺乳动物), not fish, but they swim together like fish in a school. Dolphins talk to the other dolphins in the school. They give information to the others. They talk when they are happy, sad or afraid. They say "welcome" when a dolphin comes back to the school. They talk when they play.

    They make some sounds above water. They make many more sounds under water. People cannot hear these sounds because they are very, very high. Scientists make tapes of the sounds and study them. Sometimes people catch dolphins for a large aquarium (水族宫). People can watch dolphins in a show. Dolphins do not like to be away from their school in an aquarium. They are sad and lonely. There are many stories about dolphins. They help people. Sometimes they save somebody's life. Dolphins' meat is good, but people do not like to kill them. They say that dolphins bring good luck. Many people believe this.