Waste can be seen everywhere in the school. Some students ask for more food than they can finish and others often forget to turn off the lights when they leave the classroom. They say they can afford these things. But I don't agree with them.

    Waste can bring a lot of problems. Although China is rich in some resources, we are short of others, such as fresh water. It is reported that we will have no coal or oil to use in 100 years. Think about it. I think we should say no to the students who waste things every day. Everybody should stop wasting as soon as possible.

    In our everyday life, we can do many things to prevent waste from happening. For example, turn off the water taps when we finish washing, turn off the lights when we leave the classroom and try not to order more food than we need. Little by little, everything will be changed. Waste can be stopped one day if we do our best to form the habit of saving.

    Most American children eat potatoes. But many children don't know what of the potato is the best food. Take a knife and cut from the middle of the potato a piece as thin as paper. I hold the piece between your eyes and light. You will see that the potato has skin(皮), an outside rim(边缘)and an inside part. The outside rim which is right under the skin of the potato, is the most valuable part of all. But this is often thrown away with the skin. Even the skin itself is better for food than the inside. When eating a cooked potato, if you choose the inside and leave the outside, you are throwing the best part of it. If you can't cat the whole potato, eat the outside rim first and leave the inside part.

    Many scientists believe our love of sugar may actually be an addiction (上瘾). When we eat or drink sugary foods, the sugar enters our blood and influences parts of our brain that make us feel good. Then the good feeling goes away, leaving us wanting more. All tasty foods do this, but sugar has a particularly strong effect. In this way, it is in fact addictive, and doctors suggest we all cut down on it.

    "It seems like every time I study an illness, I find my way back to sugar," says scientist Richard Johnson. One-third of adults worldwide have high blood pressure (血压), and up to 347 million have diabetes (糖尿病). Why? "Sugar, we believe, is one of the reasons, if not the main reason," says Johnson.

    Our bodies are designed to survive on very little sugar. Early humans often had very little food, so our bodies learned to keep sugar as fat. In this way, we had energy stored for when there was no food. But today, most people have more than enough. So the very thing that once saved us may now be killing us.

    So what is the solution? It's obvious that we need to eat less sugar. The trouble is, in today's world, it's extremely difficult to avoid. From breakfast cereals to after-dinner desserts, our foods are increasingly filled with it. Some manufacturers (制造商) even use sugar to replace taste in foods that are advertised as low in fat. This may make the food appear as healthier, but large amounts of sugar are often added.

    But there are those who are fighting back against sugar. Many schools are offering more fruit instead of deserts. Other schools are building facilities for students to do exercise. The battle has not yet been lost.

    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 large 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.