In most parts of the world, manystudents help their schools make less pollution.They join environment clubs.Inan environment club, people work together to make our environment clean.

    Here are some things students oftendo.

    No-garbage lunches.How many lunch bagsdo you throw away after lunch? Environment clubs ask students to bring theirlunches in bags that can be used again.Every week they will choose the classesthat make the least garbage and report them to the whole school.

    No-car day.On a no-car day, nobodycomes to school in a car including the students and the teachers.Cars givepollution to us, so remember:

    Walk, jump, bike, or run!

    Use your legs! It's lots of fun!

    Turn off the water! Do you know thatsome toilets can waste twenty to forty cubic meters of water an hour? In ayear, that would fill in a small river. In the environment clubs, students mendthose broken toilets.

    We love our environment.Let's worktogether to make it better.

    A computer can get very hot when it works on a lot of programs. It can cost a lot to cool the computer. So some scientists want to know what would happen if the heat from the computer could be used.

    Large Internet companies such as Google and Microsoft have thousands of computers. As these computers deal with information， they produce lots of heat， so they need huge cooling systems. These systems send the heat into the air.

    A company in Holland thinks paying to make the computers work and then paying again to cool them are a waste of energy. So the company developed a special device—the e-Radiator.

    Boaz Leupe， head of the company， says that e-Radiator works as a heating system and saves money. He explains that the energy is used twice—once to heat the home and once to cool the computer and that the users don't have to pay to cool their computers.

    Five homeowners in Holland are testing the heating system in their homes.

    “We pay for the computer using， so， in that way， homeowners get heating for free.” Boaz says.

    Jan Visser is one of the homeowners. “If you use the computer more， the e-Radiator producers more heat，” he says， “It cannot provide enough heat if you don't use your computer often.” But he is ready to try it. It's a great help for his family.

    The company says e-Radiators produce heat temperatures of up to 55℃. It says the system could save its users about $440 a year.

    In 1969, humans landed on the moon for the first time. Now, many other countries want to go there as well. Why?

    The moon has a lot of minerals (矿物质) and other useful things. We want to find out if we can use them. The moon is our closest neighbor in space. We can use it as a rest station. Then, we can learn more about other planets far away in space.

    The moon is 3,474 kilometers in diameter (直径). It is about one-fourth the size of Earth. If Earth is the size of a basketball, the moon is the size of a tennis ball.

    The moon has much less gravity than Earth. If you can jump 1.5 meters on Earth, you can jump 9 meters on the moon.

    The moon is very quiet. There is no sound there. There are a lot of grey rocks on it. The moon's sky is always black.

    Our moon is about 384,400 kilometers away from Earth. The total length of the Great Wall is about 21,200 kilometers. We would have to put about ____ Great Walls end to end to reach the moon!

     The world itself is becoming much smaller by using modern traffic and morden communication means (工具). Life today is much easier than it was hundreds of years ago, but it has brought new problems. One of the biggest problems is pollution. To pollute means to make things dirty. Pollution comes in many ways. We see it, smell it, drink it and even heart it.

    Man has been polluting the earth. The more people have, the more pollution becomes. Many years ago, the problem was nor so serious because there were not so many people. When the land was used up or the river was dirty in one place, man moved to another place. But this is no longer true.

    Man is now slowly polluting the whole world.

    Air pollution is still the most serious. It's bad for all living things in the world, but it is not the only one kind of pollution, Water pollution kills our fish and pollutes our drinking water. Noise pollution makes us angry more easily.

    Many countries are making rules to fight pollution. They stop people from burning coal in houses and factories in the city, and from putting dirty smoke into the air. Pollution by sulfur dioxide (So₂) is now the most dangerous kind of air pollution. It is caused by heavy traffic. We are sure that if there are fewer people driving, there will be less air pollution.

    The earth is our home. We must take care of it. That means keeping the land, water and air clean. And we must pay attention to the rise in pollution at the same time.

    All week long, it seems you sit inside at school when it is fine outside. But when the weekend comes, it is very cloudy. There is rain according to(根据) the weather report.

    Scientists studied more than 40 years of weather data(数据) from around the world. It shows weekend weather is different from weekday weather in some places.

    Part of the study involved(包括) 660 weather stations in the US. At more than 230 of these places, the weather on Saturday, Sunday and Monday was different from the weather on Wednesday, Thursday and Friday. The difference was small, but the pattern was striking enough to make the scientists take notice.

    "This kind of weekly rise and fall doesn't line up with any natural cycles, "the scientists say. Instead, they think that air pollution from human activities makes the weather become different.