You may know about "junk food" like French fries. But do you know about "junk sleep"?

    Recently, a British survey found that electronic products（电子产品）in teenagers' bedrooms are affecting（影响）their sleep. The survey was done among 1,000 British kids from 12 to 16. It found that 30 percent of them got just 4 to 7 hours of sleep every day. But doctors say they need 8 to 9 hours.

    Almost a quarter of the kids said they fell asleep more than once a week while watching TV, listening to music or using other electronic products.

    "This is very worrying." said Dr. Chris Idzikowski, "We call it "junk sleep". It means you don't get enough sleep and the quality（质量）of the sleep is bad, too. If you don't get good rest, you won't perform well in school the next day."

    The survey found that 40 percent of the kids felt tired each day, with girls between 13 and 16 feeling the worst. Nearly all the teenagers have a phone, Mp5 or TV in their bedrooms. And many of them have all three.

    Rubbish is a major kind of environmental pollution. Each person produces about 2kg of rubbish a day. We are making waste products faster than nature can break them down. And we are using up resources(资源)faster than they can he replaced(取代).

    This adds up to trouble for the environment. Where does all that rubbish go? What can be done to help dispose of(处理)rubbish? How can we make less rubbish?

    Rubbish isn't just the smelly rotting fruits, vegetables or meat that we throw away(抛弃) in our homes Those are only a small part of all tile stuff we throw away. We create other kinds of waste, in construction, mining and in our factories.

    Did you ever wonder what happens to your rubbish? Most is burned(燃烧)or buried in landfills(垃圾填埋场). Less than a quarter of our waste is recycled(回收).

    With a population of 1.3 billion(十亿), rubbish is a big problem for China. Chinese city create around 148 million tons of rubbish every year. The amount is growing at around 10 percent each year.

    Once we used about 3 billion plastic shopping bags everyday in China. The result was a great waste of resources and serious pollution. So we did something about that. Now we use more cloth bags and shopping baskets when we shop.

    In the coming years China will build waste-to-energy plants in cities to clean up the rubbish. But there's a lot more that needs to be done. And you can play a role.

    Alsten Chase has written a book about Yellowstone National Park. He is worried about the damage the fires can do to the park. He is also concerned(关心) about the park rules. These rules say that nature should decide what happens to the park. Alsten also writes that the elk herd(马鹿群) has grown too big. The elks walk on the riverbanks. They eat the new grass and roots of baby trees. The beavers(河狸) need the trees to build dams(坝).

    The dams raise the water levels. Higher water levels put more water into the soil. Wet soil helps plants grow faster. The plants offer homes and food to other animals.

    Chase thinks that the park rules would work only in a park with natural settings. He believes that Yellowstone has had an artificial(人为的) setting for a long time. The native people left. The wolves were taken away and other animals were removed. The areas of land were fenced off(隔开) and other animals added. He thinks the park rules that let herds grow too big and the fires are hurting the nature of the park.

    The park manager thinks the rules are good and that the park will be fine. Chase thinks the way the people run the park should be changed.

    Is there intelligent（有智力的）life on other planets? For years, scientists said "no." or "we don't know." But today this is changing. Seth Shostak and Alexandra Barnett are astronomers（天文学家）. They believe intelligent life exists（存在）somewhere in the universe. They also think we will soon contact them.

    Why do Shostak and Barnett think intelligent life exists on other planets? The first reason is time. Scientists believe the universe is about 12 billion years old. "This is long enough for other planets to have intelligent life, "say Shostak and Barnett. The second reason is size the universe is huge. "Tools like the Hubble Telescope（哈勃望远镜）have shown that there are at least 100 billion galaxies, "says Shostak. "And our galaxy, the Milky Way, has at least 100 billion stars. Some planets going around these stars might be similar to the earth. "

    In the past, it was hard to look for signs of intelligent life in the universe. But now, powerful telescopes（高倍望远镜）allow scientists to discover smaller planets-the size of Mars or the earth-in other solar systems, these planets might have intelligent life.

    Have beings from space already visited the earth? "Probably not, "says Shostak. "It's a long way away. However, intelligent beings may contact us in other way, such as radio signals（信号）. In fact, they may be trying to communicate with us now, but we don't have the right tools to receive their messages. However, this is changing. By 2025, we could make contact with other life forms in our universe and we might help each other. "

    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.

    On July 1, 2019, Shanghai began the waste sorting programme. There are four kinds of waste: wet waste, dry waste, dangerous waste and recyclable waste. Under the new rules, people must put their waste in the right place. Or they will be fined more than 50 yuan and less than 200 yuan.

    Sorting waste is very important. By doing so, we can take out non-degradable(不可降解的)waste and save resources(资源)In return, we can get a better environment.  ▲   Luckily. Internet companies like Wechat, Baidu and Alipay made apps to help.

    How do we use the apps? Just open one waste-sorting app and write down the keyword. Then the app will tell us the answer and why, Alipay says its waste-sorting app got one million users in just three days and the number is still growing. They are working on the app and people may use it by taking photos in the future.

    The waste-sorting programme is the talk of the whole country now. And another 21. 3 billion yuan will be used on the programme in 46 cities by the end of 2020.