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!

    Every living thing on Earth is either a plant or an animal, right? Wrong! Many organisms（有机体）in our world are neither. Some of them float through the air, and some lie hidden in the ground. They do not need sunlight to survive, and if the weather becomes too cold, they can become inactive until conditions improve.

    What are these? They are called fungi(菌类), and you see them almost every day. Many kinds of fungi seem disgusting, such as the green black things that appear on the food which are left too long in the refrigerator. But other kinds are not so bad. For example, the yeast that is used to make bread and mushrooms (蘑菇) are both fungi.

    What makes fungi different from plants and animals? An animal can move around by itself. Fungi get around too, but they don't have feet, wings, or tails. They have to wait for wind or some other outside force to move them. Plants are different from fungi because they have chlorophyll（叶绿素）. It helps them make food from the energy in sunlight. Fungi do not have chlorophyll.

    Some fungi are bad, while others are not. Some fungi cause diseases, such as athlete's foot, which makes feet uncomfortable. Other kinds of fungi can be used to make medicines, which have saved many lives.

    Fungi clean up more than wounds, though. They are the world's first recyclers. Without fungi, our world would be a mess. Since fungi cannot make their own food as plants do, they must get their food elsewhere. Many fungi get their food from dead plants. They break them down and turn them into soil. The fungi get a meal, and the world gets a housecleaning.

    How do you keep cool during summer? Air conditioners or electric fans are good 1 in modern society. But 2 that, people could only use fans.

    Over 3,000 years ago, fans began to 3 They were made of feathers (羽毛), bamboo or silk. They came in different 4 , including round and square.

    Later, with the invention of paper, folding(可折叠) paper fans became popular5 the Song Dynasty.  There are usually beautiful 6on fans. Some are landscapes (风景). Others are flowers and animals. Moreover, many great people including Su Dongpo, a poet of the Song Dynasty, and Tang Yin, a scholar (学者) and painter of the Ming Dynasty, once painted their masterpieces(杰作) on fans. This made fans not only 7 tools in daily life but also great artworks.

    So, with its value of beauty, people take fans as a 8 of status(地位). That's why in old China, emperors and scholars often held fans.

    Today, fans are also great collectors' items(藏品) and gifts. On the opening ceremony of the 2008 Beijing Olympic Games, folding fans were9 to leaders and officials (官员) of other countries. While they were 10 fans to get cool, they were also experiencing Chinese culture.

    A new rubbish sorting system (垃圾分类系统) has been put into use in Fangchengyuan Community in Beijing. Local people not only sort their rubbish, but also put QR codes (二维码) on it.

    "When the rubbish is collected and the codes are scanned (扫描), I will get reward points to exchange for small gifts and even some money," one of the local people told reporters. "It's really creative and encouraging."

    This smart system has been carried out in 350 communities in Beijing. The capital of China has joined a list of cities in the country that take action to support rubbish sorting. For example, Shenzhen and Shanghai have made laws to punish people and organizations for not sorting rubbish correctly.

    China produces quite a lot of rubbish every year. Much of the rubbish is buried (填埋) in soil or burned without being sorted. Landfills (填埋场) take up a lot of land and have a risk of polluting the soil and water nearby. And burning rubbish can produce harmful gases. Through rubbish sorting, we can reduce the use of landfills and air pollution.

    What's more, rubbish sorting saves resources, which could bring economic benefits (经济利益). For example, a ton of waste paper can be reused to make about 850kg of paper, saving 17 trees and 50 percent of water. Because of their benefits, some countries have developed successfully sorting systems.

    In Australia, every family is provided with three rubbish bins—the red lid (盖子) bin for "general waste" like food and plastic bags, the yellow lid bin for "recyclable (可回收利用的) waste" like steel and glass, and the green lid bin for "green waste", such as grass and leaves. On the street, the bins are printed with pictures of the things that are allowed inside. It makes recycling quite easy.

    Many scientists think that the Earth is getting warmer and warmer. If the change continues, the natural world and human society will face danger. Scientists believe human activity is responsible for the climate change. We produce too many greenhouse gases. They keep heat in the air and make the Earth warm.

    Many of the world's governments agree. And they want to solve the problem. So from 7 to 18 December, 2009，they held a conference in Copenhagen, Denmark to talk about global warming and climate change.

    Representatives(代表) from 192 countries and regions went to the meeting. Although they have not reached an agreement, the Copenhagen Accord(《哥本哈根协议》) was an important beginning to save the Earth. It was made by a small group of countries including China，the USA，India, Brazil and South Africa. Some other countries at the conference also showed support.

    What are the key points of the Copenhagen Accord? The accord limits global temperature increases to 2C by 2050. Scientists think it could help the world to avoid serious climate change.

    The accord also says that developed countries must promise to cut greenhouse gas emissions(排放) to the UN by 31 January, 2010. The accord asks developed countries to give money to help developing countries.

    Many countries and organizations are disappointed that the conference didn't reach a legal document(法律文书). And they think the accord is not clear enough about its goals.

African leaders are worried that the goal of a 2℃ global temperature increase isn't good enough, because it will mean a much higher increase in temperature across Africa. This could cause big problems like food and water shortages across the continent.

    Still, UN Secretary General believes the conference was an "improvement".

    "Finally we reached a deal," Ban said," the accord may not be everything everyone had hoped for, but this is an important beginning."