Don't be surprised if you see a car going down the road without a driver in Beijing these days.In march, 2018, baidu was given a license to test its self-driving cars in Beijing, China Daily reported.

    Self-driving cars have been in development since 2010, when google announced that it was making such cars. Since then, companies like Tesla, Uber and Baidu have been working to produce and test their own self-driving cars.

    Self-driving cars are expected to change the way we get around. They are safer and more environmentally friendly than regular cars. They can remove the stress(压力) of driving and allow disabled or blind people to get around more easily.

    But self-driving cars have their own disadvantages as well. In one test, researchers pointed a laser pointer（激光棒） at the car's sensors（感应器） while it was moving. The car mistakenly thought that the laser beam（波束） was in its way and slowed down or changed directions.

    The software(软件) that is used to direct the cars may not be safe enough. Reported Live science. Sometimes, without any reasons,it may break down when we use our computers or smartphones. If the software in a self-driving car happened to crash. The results could be deadly.Maybe improvements to the software could solve this problem.

    Humans and animals need oxygen to exist. Without it, most living things will die. But where does oxygen come from'? Trees. Trees can take in much carbon dioxide which may be bad for our environment and produce oxygen for us to breathe.

    All people know that trees are important to us. Scientists believe humans cannot live if there are no trees on the Earth.

    Trees are a major source(来源) of food. Apples, oranges, lemons all come from trees.  Humans and animals knew how to get food from trees many years ago.

    In fact, many kinds of important medicine come from trees too. Some special things on trees can be used to produce medicine. Also, trees can make the world beautiful and relaxing. They help protect the soil.

    One fresh sunny day, while I was swimming in the water, I felt something special going through my gills（腮）. It was a different kind of water. I also found many of my friends became sick. Some of them were dying. I was thinking about what I should do to save my friends, so I decided o do some research for my underwater life.

    My research started. At first, I noticed there were many bottles, cans and other kinds of rubbish in the water. Then I went on. I got closer and then I tasted many different kinds of liquid（液体）. To my surprise, I noticed a man pouring some liquid into the water. Others also saw him doing so and they decided to follow him. I hated it! I wish I could have told them that it was killing us!

    I think it is so stupid for people to do this to the earth that they are living on! I can't understand why they are doing this. Humans should stop throwing waste into the lakes or rivers. I want to have a normal life with my friends. People should stop being so selfish and care about the environment. If they do that, everyone will be fine and will have nothing to worry about. I suggest they follow my words. If so, I believe everyone will be able to live a happy life.

Would it surprise you to learn that, like animals, trees can communicate with each other and pass on their wealth to the next generation—their young trees?

    Suzanne Simard, forest ecologist(生态学家) at the University of British Columbia, explains how trees are much more complex(复杂的) than most of us ever imagined. Although Charles Darwin(达尔文) thought that trees are competing for survival of the fittest, Simard and her team have made a new discovery and showed just how wrong he was. In fact, the opposite is true: trees survive through their group work and support, passing around necessary nutrition(营养) such as nitrogen(氮) and carbon "depending on who needs it".

    Nitrogen(氮) and carbon are shared through miles of underground fungi (真菌) networks. This makes sure that all trees in the forest ecological system give and receive just the right amount to keep them all healthy. This system works in a very similar way to the networks of neurons (神经元) in our brains, and when one tree is destroyed, it influences all.

    Simard talks about "Mother trees". These are usually the largest, oldest plants that on which all other trees depend. These "Mother trees" are connected to all the other trees in the forest by this network of fungi, and may manage the resources of the whole trees and plants in the forest. She explains how these trees pass on the wealth to the next generation, transporting important resources to young trees so they may continue to grow. When humans cut down "Mother trees" without paying attention to these highly complex "tree societies" of the networks on which they feed, we are reducing the chances to save the whole forest.

    "We didn't take any notice of it," Simard says sadly. "Mother trees" move nutrition into the young trees before dying, but we never give them chance. If we could put across the message to the forestry industry, we could make a huge difference towards our environmental protection efforts for the future.

    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.