Keep away from a fire. You could fall down and burn yourself on the fire.
   If you are driving when an earthquake happens, stop the car if it's safe. Stay inside your car until the earthquake stops, and don't drive near bridges. Try not to stop by power lines or trees. These could fall and hurt you.

    The world itself is becoming much smaller by using modern traffic and modern communication equipment(通讯设备). Life today is much easier than it was hundreds of years ago, but it has brought new problems. One of the biggest is pollution. To pollute means to make things dirty. Pollution comes in many ways. We see it, smell it, drink it and even hear it. Man has been polluting the earth. The more people, the more pollution. Many years ago, the problem was not so serious because there were not so many people. When the land was used up or the river was dirty in one place, people moved to another place. They are 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 against pollution. They stop people from burning coal in houses and factories in the city, and from putting dirty smoke into the air.

Pollution by SO₂ is now the most dangerous kind of air pollution. It is caused by heavy traffic. It is 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 take care of the rise in population at the same time.

    These days, many students like playing 3D games. Do you know what 3D games are like? In most 3D games, game players need to control (控制) a character. The character can be a robot or a soldier (士兵). Game players usually use the mouse to make the character move around in his own world. Game players can find things such as food and weapons (武器) to help them go on with the game. The character can go straight, sit down, turn left, turn right or pick up things in the game.

    Some 3D games have many levels (等级). The character needs to finish different goals for each level. Game players can play against their computers, and sometimes they can play with other players on-line. It's great fun to play 3D games. But playing 3D games for long is not good for our study.

    Coloring is an activity that children worldwide have long enjoyed. With a picture already made for them, kids simply chose a crayon, pencil or marker of their favorite color and fill it in. Today, it also becomes more and more popular among teenagers and even adults, who are enjoying relaxing hours of coloring. In December, five of the top ten best-selling books in the United States were coloring books.

    They are fun, but are coloring books good for you?

    The good feedback(反馈)from customers is encouraging. Trina Lucida, a popular artist creating coloring books, says that many of her customers are buying the coloring books for others who are sick or going through a hard time. She adds that the "big idea" behind her latest book is to encourage people to do something creative.

    Lucida is right, according to Allan Rohan, a psychology(心理学)professor. "Many customers think of coloring books as a new creative stage," he said in an interview, "but what's more important is that people spend time coloring in order to reduce stress after a long day." Research shows that coloring can reduce stress by guiding people to focus on(专注)one simple task. When a person is filling in a flower with a light purple color, he focuses on the flower and forgets about all his troubles in life.

    Experts add that coloring may relieve a certain kind of pain. Doing the coloring helps people relax their mind and calm down. Also, coloring helps people's brain in a healthy way. The shape of the drawing makes one side of the brain active, while the color of the drawing improves the other. Coloring can bring out your imagination and take you back to your childhood. Interesting, isn't it?

    "It's very relaxing," said Susan Jackson, a big fan of Lucida's coloring books. "Coloring frees my mind. And it's not just to try to fill blank(空白的)pages. The pictures make me happy and there is just something about them. So I'm saving the pictures I like best to the very end."

    Sheridan is a town in Indiana, USA. There are lots of trees near the public schools in the town. Their leaves turn sunlight into energy.

    In Sheridan, the Sun not just provides energy for plants. It keeps schools running, too. The schools use solar panels(太阳能电池板) to turn sunlight into energy.

    The science behind solar energy is not new. But Sheridan Community Schools is the first school district (学区) in Indiana to be completely solar-powered. The district finished putting in solar panels for all three of its schools in 2016. Some of the panels can turn to follow the Sun across the sky.

    In 2008, fewer than 1,000 schools used solar power. By 2014, there were 3,727 schools with solar panels in the USA. These numbers come from a report by The Solar Foundation. Roxie Brown, a programme director there, said that the number of schools with solar panels has continued to go up since 2014.

    Solar energy has some advantages over other energy sources (来源). Sunlight is a renewable source, which means it won't run out. Solar panels don't harm the environment. Also, sunlight is free. So by using solar power, schools can save money on energy costs. Brown thinks more schools should run on solar energy. "The Sun is Earth's energy source," she says. "We're trying to make it the energy source for our houses, cars and schools, too."

    But using solar energy isn't always easy. Solar panels can be expensive to put in. The panels also take up space. But for many schools, going solar is worth it.