Look up in the sky. Do you see any clouds? What do they look like ?Some clouds are fluffy（绒毛状的）and white, like cotton balls. Others are dark, almost black, and make you hold an umbrella. At sunrise and sunset, clouds can look red, purple, or yellow，as if they were colored with crayons. But what are clouds anyway?

   You can't reach out and touch the clouds, but you can make your own in a bottle.

   You need :

   An adult helper

   A huge, empty glass container（容器）

   A metal strainer（滤网）

   Hot water

   Ice

   Do these:

   Step1. Have your helper fill the container with hot water ,leave it there for two minutes, then pour out most of the water, leaving just an inch or two at the bottom of the container.

   Step2. It's your turn now. Put the strainer over the mouth of the container. Fill the strainer with ice. Watch the container.

What happened?

A cloud formed in the container! Some of the hot water at the bottom of the container turned into the hot water vapor. The water vapor rose and met with cold air coming off the ice. When the water vapor condensed（凝结）,it formed a cloud. Hot air rises ad carries with it lots of water vapor. The higher the air rises, the more it cools down. Soon the cold air can't hold all the water vapor so it starts turning into tiny water drops, and becomes a cloud.

    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!

B

    Have you ever stayed in a hotel? Most Chinese hotels often provide guests with things like disposable (一次性的) toothbrushes, toothpaste, shampoo and slippers. Many guests like the idea because they don't have to bring their own. But, if you travel to Beijing, remember to bring your own things. Starting from June, some hotels in Beijing will no longer provide guests with these disposables. They want to ask people to use less disposable things.

    Many disposable things are made of plastic. People throw them away after only using them once. It is a waste of natural resources (资源) and is very bad for the environment. Do you know, one Chinese person makes as much as 400kg of waste a year! Most of that waste comes from disposable things. In Beijing, people throw away about 19,000 tons of plastic bags and 1,320 tons of plastic lunch bowls every year! Plastic can take between 100 and 400 years to break down. So the less plastic we throw out, the better. So, wherever you travel, bring your own things and use them again and again.

    Back at home and school, you can also do something to make our world a better place. Try to do these things in your daily life: Use cloth shopping bags, not plastic ones. After using a plastic bag, wash it out and let it dry. Then you can use it over and over again. Do not use paper cups. At your school canteen（食堂）, use your own bowl and chopsticks instead of disposable ones.

    Lately, people have entered the forests where chimpanzees live. The chimpanzees have been getting sick because of people's diseases. In addition, people are hunting chimpanzees. Their number is becoming smaller and smaller.

    Chimpanzees live in the plains and forests of Africa. They eat many kinds of foods, from plant leaves and seeds to insects and even other small animals. Chimpanzees' favourite food is fruit.

    Chimpanzees are very clever and they can use tools well. They can catch bugs by using sticks, and break nuts by using rocks.

    The world's forests are much smaller than they were before. Roads were built in deep forests, so people start to enter the forests where chimpanzees live. That may lead to many problems. One problem for chimpanzees is that they can easily catch people's diseases and die.

Chimpanzees are much closer to people than monkeys.

    As it's easier for people to enter forests, they hunt more often. Young chimpanzees are caught to be pets or for scientific research. The young ones are taken away from the forests, and the adults are killed. Chimpanzees are likely to disappear in the future.

    Cars make our lives more convenient. But they can also be a problem. For example, fossil fuel(化石燃料) cars mainly cause air pollution.

    To improve the environment, many countries are developing electric vehicles (EVs,电动车). Among them, China is taking a leading role and has created the world's largest EV market.

    Last year, over 40 percent of the 753,000 EVs sold in the world were sold in China, more than twice as many as the number sold in the United States.

    "Filling up a fossil fuel car with gas(汽油) is more expensive than charging( 充电) an electric car，" said Wu Hao，who bought an electric car this year.

    However, there are still some problems. It can be hard to find charging piles(充电桩) and the cars can't go far before needing to be recharged.

    Some of these problems are being solved. In 2014，China had 31,000 charging piles. Now China has the world's largest EV charging network, with more than 167, 000 charging piles in total.

    Developing EVs is one of many efforts that China has made to cut down pressure on its environment after the government promised to stop increases in carbon dioxide emissions(二氧化碳排放量) by 2030.

    "As China goes, so will the world's car industry," The Wall Street Journal said. China has taken a leading role in the world's electric vehicle industry.