Many people are surprised when they find that the Internet was set up in the 1960s. At that time, computers were large and expensive. Computer networks didn't work well. If one computer in the network broke down, then the whole network stopped. So a few network system had to be set up. It should be good enough to be used by many different computers. If part of the network was not working, information could be sent through another part. In this way computer network system would keep on working all the time.

At first the Internet was only used by the government, but in the early 1970s, universities, hospitals and banks were allowed to use it, too. However, computers were still very expensive and the Internet was difficult to use. By the start of 1990s, computers became cheaper and easier to use. Scientists had also developed software that made "surfing" the Internet easier.

    Today it is easy to get online and it is said that millions of people use the Internet every day. Sending e-mails is more and more popular among young people. The Internet has now become one of the most important parts of people's life.

    Nearly all our food comes from the soil. Some of us eat meat, of course, but animals live on plants. If there were no plants, we would have no animals and no meat. So the soil is very necessary for life. The top of the ground is usually covered with grass or other plants. There may be dead leaves and dead plants on the grass. The waste matter(粪) from animals also falls on it.

    All soil needs food. If we do not give it any, the plants will be weak. Farmers found that animals' waste is the best food for the soil, but chemical fertilizers(化肥) are also very useful. The same crop（庄稼）should not be grown in the same place every year; it 's better to have a different crop. A change of crop and the use of a good fertilizer will keep the land good.

    When you are on a long road trip or in a traffic jam during a daily-commute ， it may seem harmless to connect your phone to your car's USB port．But unless you really need to use your phone，charging(充电)your iphone during your commute could be a big mistake．

    Why? For starters，the USB port in our car probably provides less electricity than your phone really needs to charge．As a result，your phone might stop working while it charges.

    Many people may notice that on their way home from work their phone charged very little during their 30-60 minute commute，"says Brad Nichols，an engineer at Staymobile．"It is mostly because that the phone is using more power than the car charger isproviding it．"

    Nichols also says that your phone could receive too much power，especially if you are using a cigarette lighter port to charge up．Most cigarette lighters can provide more power than most chargers can afford．If a charger cannot keep providing the proper power, it may make the phone broken．

    Charging your phone could do harm to your car's battery(电池)，too．This usually isn't a big deal for those who own new cars with healthy batteries，Nichols says．But if your car is older，you might not want to charge your phone through its USB port．

    Most importantly，it's not safe to use your phone while driving．"Anytime a person's hands leave the wheel or eyes leave the road，it becomes dangerous for them and the other people around them," Nichols points out．Bottom line：Play it safe，and wait until you get home to charge your phone．

    In the universe, as we all know, there is the Sun, the Moon, the Earth and a good many stars. Through our geography lessons, we know the Earth goes around the Sun, and the Moon goes around the Earth. We have day and night because the Earth keeps turning all the time. When our part of the Earth turns to the Sun, it is day. When our part of the Earth turns away from the Sun, it is night.

    Just because the Moon is closer to the Earth than the Sun, it looks much bigger than the Sun. Big things will look smaller when they are further, and small things also look bigger when they are nearer.

    The Sun is big enough to give out very strong light. The Moon can't give out any light at all, but it looks quite bright, too. Why? In fact, the light from the Moon comes from the Sun. The Moon looks much bigger and brighter than the stars. But actually the stars are much bigger and brighter than the Moon. They look smaller than the Moon also because they are farther away from the Earth.

    There are many other planets in the universe. But of all the planets, only on the Earth there are living things and people can only live on the Earth, too. But at 9: 00 a. m. on October 15th, 2003, Chinese pilot Yang Liwei was sent up to space. He stayed there for over 21 hours. It was the first time for Chinese to get into space.

    On April 2, we said goodbye to Tiangong I, China's first space lab. According to the China Manned Space Agency (中国载人航天), Tiangong I re-entered the Earth's atmosphere (大气层) and some of its debris (碎片) fell into the South Pacific Ocean.

    There are many spacecraft (宇宙飞船) that are still in orbit

     (轨道) above the Earth. After finishing their trips, they will all re-enter the Earth's atmosphere like Tiangong I.

    There are two types of re-entries: controlled re-entry and uncontrolled re-entry.

    Some satellites and manned spacecraft come back to the Earth in a controlled re-entry. Experts calculate (计算) the path of the falling spacecraft and its speed. Thy can guide the spacecraft to fall in a chosen area.

    Some spacecraft may have problems while in space after a certain amount of time. These spacecraft come back in an uncontrolled re-entry. It is hard to tell when and where these spacecraft will fall until the last few hours. The US space station Skylab came back partially uncontrolled in 1979. Parts of the station fell in western Australia, but no one was hurt.

    During re-entry, most of the spacecraft will burn up while passing through the Earth's atmosphere. Only a small amount of the debris will reach the ground. The debris typically ends up falling into the ocean, China Daily reported.