Napoga is a 12-year-old girl in Ghana(加纳), Africa. It is hard for her family to get clean water. Every morning, she leaves home at half past five to get clean water for her family in a village far away. It takes her six hours to get enough clean water for daily(日常) cooking and drinking. She has no time to go to school or to play with her friends. Millions of people in the world are like Napoga. They can't get enough clean water to keep healthy.

    Earth Day is on April 22. But on all other days, we must also remember it. The water we use is the most important natural resource(自然资源) on the earth.

    Water covers 70% of the earth's surface(表面). But most of that is sea water. We can't use it for very many things. Fresh water covers only 1% of the earth's surface.

    You probably feel lucky that your life isn't as hard as Napoga's. But that doesn't mean you don't have to worry about water. We all face serious water problems. One of them is water pollution. All kinds of things from cars, factories, farms and homes make our rivers, lakes, and oceans dirty. Polluted water is very bad for people to drink. And dirty water is bad for fish, too. Now, 34% of all kinds of fish are dying out.

    How do cars and factories make our water dirty? First, they pollute the air. Then, when it rains, the rain water comes down and makes our drinking water dirty. Dirty rain, called acid rain(酸雨), is also bad for plants, animals and buildings.

    Scientists say that in 30 years, more than half of the people in the world won't have enough clean water. We have to learn how to save more water for ourselves and our children. Here is some advice for saving water:

●Turn off the water while you brush your teeth. You can save as much as 450 liters(升) each month.

●Leaky taps(漏水的龙头) waste a lot of water. Fix them right away!

●You can easily cut your 10-minute showers(沐浴) in half—and you'll be just as clean.

●When you wash dishes, don't let the water run.

●Only wash clothes when you have a lot to wash. If your washing machine isn't full, you're wasting water!

    Computer technology has become a major part of people's lives. This technology has its own special words. One example is the word " mouse". A computer mouse is not a small animal that lives in buildings and open fields. It is a small device (装置) that you move around on a flat surface in front of a computer.The mouse moves the cursor (光标) on the computer screen.

    Computer expert Douglas Engelbart developed the idea for the mouse in the early nineteen-sixties. The first computer mouse was a carved block of wood with two metal wheels. It was called a mouse because it had a tail at one end. The tail was the wire that connected it to the computer.

    Using a computer takes some training. People who are experts are sometimes called hackers. A hacker is usually a person who writes software programs in a special computer language. But the word" hacker" is also used to describe a person who tries to steal information from computer systems.

    Another well known computer word is Google. It is the name of a popular search engine for the Internet.People use the search engine to find information about almost any subject on the Internet. The people whostarted the company named it Google because in mathematics, googol, spelled g-o-o-g-o-l,is an extremely

    large number. It is the number one followed by one hundred zeros.

    When you "Google" a subject, you can get a large amount of information about it. Some people like to Google their friends or themselves to see how many times their name appears on the Internet. If you Google someone, you might find that persons name on a blog. A blog is the shortened name for a Web log. A blog is a personal Web page. It may contain stories, comments, pictures and links to other websites. Some people add information to their blogs every day. People who have blogs are called bloggers.

    How much sleep do we need? We are all different. Some people need only three hours of sleep a night. Others need ten hours of sleep a night. Most Americans sleep an average(平均) of seven to eight hours a night. After the age of fifty, the average sleeping time goes down to 6.5 hours a night.

    Most people have a bad night when they cannot fall asleep(睡着). The name of this problem is called insomnia.

    This isn't a new problem .Many famous people in history had insomnia .Some of these people had special ideas to make them sleep .Benjamin Franklin, the famous inventor had four beds. He moved from one to another to fall asleep .King Louis XIV(国王路易十四)of France had four hundred and thirteen beds and hoped to fall asleep in one of them .Mark Twain, the famous American writer, had a different way. He lay on his side across the end of his bed.

    Big data (数据) is a lot of sets of information that are put together so they can be used by a computer program. The computer program looks for different kinds of answers or patterns in the data. Big data can have different kinds of information from many sources, such as information that comes from schools, social media sites, companies, and governments. One set of data can have people's names and addresses. Another set can have what they like, where they go to school, and how much time they spend on the computer.

    Big data can be used in many ways. The government uses it to understand how many people travel on buses or trains. This information is then used to make bus or train systems better. Some schools use big data to understand which children may need extra help in class. The teacher can then give certain students more help or support so those students can succeed in school. Companies use big data, too. It helps them understand who buys their products. For example, one company uses weather data to see when people eat the most ice cream.

    Big data can be used for good reasons. Some hospitals use big data to predict if a baby who is born too early will get sick. The hospital can then take extra steps to take care of that baby so he or she does not get sick. Big data can also be used for bad reasons. It can be used to predict which kinds of people are likely to break the law or hurt others, even if they have not done anything wrong.

    How can big data be used for good and bad things? It is because the computer programs used to look at big data and understand it are written by people. People think a certain way. Because they think a certain way, they build a model of those ideas. These ideas are then used to look at the data. Sometimes, these ideas are helpful for people or businesses. Other times, bad ideas can cause problems for certain groups of people.

    After years of research and testing, the hybrid car was developed and put on the market. It's an interesting and exciting new improvement in today's world as we look for better ways to protect the quality of the air we breathe and save our natural resources.

    The quality of our air is affected by many different things. But one of the largest sources of air pollution is the burning of fossil fuels such as coal and gasoline which is used to power a car's engine. The EPA has set national standards to help control the level of harmful pollutants sent off into the air, and the automobile industry has acted by producing a hybrid car that uses less gas and therefore causes less pollution.

    A hybrid car is a combination of a regular car that runs on gasoline and an electric car that is battery powered. Some people tend to think that since the hybrid car is partially electric, you have to plug it in to charge it. But that's not how it works. The 144 volt battery pack is actually recharged through the energy that is produced when the car's brakes are used. This is referred to as "regenerative braking", because it produces electricity.

    Although the hybrid car still runs on gasoline most of the time, this helps it use less gas than a regular car. When the driver stops at a traffic light, the engine automatically shuts off to save fuel. Then, as soon as the driver puts the car in gear and touches the gas pedal, the engine starts back up.

    Have you ever ridden in a car with someone who ran out of gas? That probably wouldn't happen if you were riding in a hybrid car. It flashes a warning on its computer screen that says, "I am low on gas". When it completely runs out, the warning reads, "YOU ARE NOW OUT OF GAS!" Then the electric power supply kicks in to let the driver travel a few more miles to a gas station.

    How green are you？Do you know how to be green？

    We all need a healthy environment, but we produce waste every day and it does harm to our environment. Though we are young, we can still do something to help. In fact, even the simplest everyday activities can make a real difference to the environment. Here are some ideas for you.

    Reduce

    Reduce means" use less". Don't waste things. This saves money and reduces pollution and waste going into the environment. Before we buy something new, think whether it is really necessary﹣or maybe the old one will be just as good! When we do buy things, choose local products if possible, and try not to buy too many things from abroad.

    Reuse

    Reuse means" use again". Use things for as long as possible. When we buy things, make sure that they last a long time. We should look after them so that they will last, and we should repair them if we can instead of throwing them away and buying new ones. Don't use a paper cup of a paper bag. It's better to use a china cup and a lunch box because you can use them again.

    Recycle

    Recycle means" change things into something else". Though it takes energy to change something into something else, it's better than throwing things away or burning them. Find out what can be recycled in your neighborhood and take part in recycling programmes. We should also buy products made from recycled materials, such as recycled paper, to help save trees.

    So please remember these three words: reduce, reuse and recycle.