Our children and grandchildren may not have a chance to visit many of the most famous places around the world. War, weather, age, traffic and pollution damage (破坏) these famous places. If we do nothing, they may even no longer remain. But looking after these places often costs more than one country can afford.

    In the early 1970s, world governments decided that if they joined together, they would be able to preserve (保护) our history. If every country paid some money, they said, it would be possible to look after important historic places. For this reason, countries around the world united to form the World Heritage Organization in 1972. Today, the organization helps to protect and rebuild the most important places from our history.

    However, one of the biggest problems for historic places is vandalism. That is to say, people sometimes enter these places and damage the buildings. At some places, such as Stonehenge in England, governments have built high fences to protect it from vandals.

    There are many different ideas about how to solve the problem of vandalism. Some professors say that if guards keep walking around these places, vandals won't be able to get in. Some professors say that if they fix more television cameras, they won't need so many guards. Others say that the best way is education. If people learn to respect history, they won't damage it. They will also want to spend money looking after old places. For this reason, the World Heritage Organization helps to spread information about the value of historic places.

    Technology is developing fast and it has become an important part of our life. Then what will the world be like in the future?

    3—D food will be both delicious and nutritious(有营养的). We can use 3—D printers to print some basic materials.    ①    And we can go further. Scientists belive that we just need to turn on a printer in the kitchen and then we can enjoy our favourite food whenever we like.

         ②      5G network will allow many more people to get information. Big companies like China Mobile and China Unicom will start to offer 5G. It is said that promises download speeds 10 to 20 times faster than 4G. For example, we can download a film within just 1 second. But with a 4G network, it takes a few minutes. There will be much bandwidth (带宽) and we can get unlimited (无限的) information.

    Underwater cities will provide more space. The earth is becoming more and more crowded. We may turn to underwater homes, which will be built as low as 15 of the sea can be used to provide power for the homes.

         ③      For us common people on the earth, the dream of travelling around space will come true. In the coming years, spacecraft will be as popular as buses, trains and planes. We can leave our home and enter space to take an adventure (冒险). And even we will get used to living there.

    A robot will be a part of life.  Robots can do many of the same things as we humans do like driving cars. But they will be used in other areas as well. They will be able to think. They can tell the difference between right and wrong. They can feel       ④        In a word, just as Jules Verne said, "Anything one man can imagine, other men can make real."

    When you look at the sky at night, the Moon looks bigger than the stars. Actually (实际上), the Moon is much smaller than the stars and the Sun. It's much smaller than the Earth. But the Moon is much closer to us than any star. That is why it looks so big. If you hold a coin close to your eyes, it looks big. If you look at it across the Moon, it looks small.

    The Moon moves around the Earth. It makes one trip in about four weeks. The Moon looks flat to us. But it is a round ball, like the Earth.

    People once thought the Moon had fire (火) on it. They thought the fire made it bright. Now we know the Moon is like a mirror. It gets its light from the Sun.

    Our sunlight comes from the Sun, too. What is the Sun? The Sun is a star. The stars we can see have their own light. There are many big stars we cannot see. Their light has burned out. Others are still bright, but they are so far away that we cannot see them. The Sun looks bigger and much brighter than other stars in Galaxy because it is the nearest of all stars. The Sun and the other stars we see are very hot, but the air around us saves us from the heat of the Sun.

    The Sun gives us light and warmth (温暖). It makes plants grow and turns leaves green. It makes life possible on the Earth. It is a life giving star.