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    Many children spend a lot of time watching or playing with electronic media –from televisions to video games, computers and other devices（设备）.

    So, it is natural that parents should wonder about the time children spend looking at a TV or computer screen. Americans say “screen time” when they talk about any time children spend in front of an electronic device.

    Perhaps parents can stop worrying so much about screen time, at least for older boys and girls. In October 2016, the American Academy of Pediatrics (AAP) listed several suggestions for parents and child care workers. Here are some of the suggestions.

●Avoid digital media use in children younger than 18 to 24 months.

●For children aged 18-24 months, avoid letting the child watch media alone. And avoid using media as a way to comfort your child.

●For children two to five years of age, allow one-hour screen time on “high-quality（质量）programming” a day and watch it with your child.

●For children aged 6 and older, don't spend too much time using media. Also, make sure that screen time does not take the place of healthy sleep, exercising, doing homework and other activities.

●Make sure to have media-free time together as a family, such as dinner or driving. Also make some areas of the home media-free. Turn off you child's electronic devices an hour before bedtime.

    My house is made of wood, glass and stone. It is also made of software.

    If you come to visit, you'll probably be surprised when you come in. Someone will give you an electronic PIN to wear. This PIN tells the house who and where you are. The house uses this information to give you what you need. When it's dark outside, the PIN turns on the lights nearest you, and then turns them off as you walk away from them. Music moves with you too. If the house knows your favorite music, it plays it. The music seems to be everywhere, but in fact other people in the house hear different music or no music. If you get a telephone call, only the nearest telephone rings.

    Of course, you are also able to tell the house if you want something. There is a home control console (控制台), a small machine that turns things on and off around you.

    The PIN and the console are new ideas, but they are in fact like many things we have today. If you want to go to a movie, you need a ticket. If I give you my car keys, you can use my car. The car works for you because you have the keys. My house works for you because you wear the PIN or hold the console.

    I believe that several years from now on, most new homes will have the systems that I've put in my house. The systems will probably be even bigger and better than the ones I've put in today.

    I like to try new ideas. I know that some of my ideas will work better than others. But I hope that one day I will stop thinking of these systems as new, and ask myself instead, “How did I live without them?”

    Is your TV connected to the Internet? What about your chair, or your fridge? Probably they are not. But in the future, most things in your home may be connected, thanks to the so-called "Internet of things".

    The Internet of things may be coming sooner than you think. Earlier this year, Samsung CEO spent a lot of time talking about the Internet things. He said that three years from now, every Samsung product will be part of the Internet of things, no matter whether it's a remote control or a washing machine.

    So, how do household objects that are part of the Internet of things work? Well, think of a common chair. When connected to the Internet, the chair warms up when it knows the user has just walked into the room and is feeling cold.

    An Internet-connected camera could help people feel safer in their homes. It can know people's faces and has an infrared sensor（红外传感器）, so even if it's dark it can see when someone passes by and send you a message on your smart-phone to let you know who's there. If the person is someone you don't know, it can tell you that, too.

    But according to MIT Technology Review, whether companies are connecting dog food bowls or safety systems to the Internet, there may be some problems. For example, many early connected-home objects don't have much built-in security, which means they could be hacked（攻击）. Moreover, it could be difficult to get these new machines to work together especially when they are made by different companies. To fight this, many companies have joined the Open Interconnect Consortium, which had 45 members by late 2015.

    So, picture this: you enter your home. The temperature changes to make you feel comfortable. Your favorite music starts playing for you. Do you think that this would be a good thing? It may happen sooner than you think.

    Building an app is a big project. If you want to build the next great smartphone app, you need a plan. First, think about the kind of app that you want to build. Will your app be a game? Will it be for business? Then make a schedule(日程安排)for building the app. You need plenty of time for research before you are ready to build.

    Now you're ready to make the app. Building an app is like a puzzle(拼图)with many different parts. You can build it yourself or find a company to help you. There are many videos and websites that can teach you to build one. Some websites provide "building blocks" for app developers. As you build, you pick blocks from the website and put them in your app.

    After you build your app, you need to check it carefully. Look for bugs. Most apps have several problems to fix. Show your app to people. Ask their opinions. Mike sure everything works before letting people download it. There are so many tools that can help you build apps. Having the right tools will make the work easier. Now almost anyone can make a new app.

    How do you keep cool during summer? Air conditioners or electric fans are good 1 in modern society. But 2 that, people could only use fans.

    Over 3,000 years ago, fans began to 3 They were made of feathers (羽毛), bamboo or silk. They came in different 4 , including round and square.

    Later, with the invention of paper, folding(可折叠) paper fans became popular5 the Song Dynasty.  There are usually beautiful 6on fans. Some are landscapes (风景). Others are flowers and animals. Moreover, many great people including Su Dongpo, a poet of the Song Dynasty, and Tang Yin, a scholar (学者) and painter of the Ming Dynasty, once painted their masterpieces(杰作) on fans. This made fans not only 7 tools in daily life but also great artworks.

    So, with its value of beauty, people take fans as a 8 of status(地位). That's why in old China, emperors and scholars often held fans.

    Today, fans are also great collectors' items(藏品) and gifts. On the opening ceremony of the 2008 Beijing Olympic Games, folding fans were9 to leaders and officials (官员) of other countries. While they were 10 fans to get cool, they were also experiencing Chinese culture.

    Artificial intelligence(AI)(人工智能)is the ability of a computer program or a machine. The computer or the machine with AI can think and learn. It is also a field of study that tries to make computers "smart". John McCarthy, a scientist, came up with(提出)the name "artificial intelligence" over 60 years ago. Many things such as learning and problem solving can be done by computers, though not in the same way as people do.

    An unusual goal of AI research is to create computer programs. They can learn, solve problems, and think logically(逻辑地). At present, Al can successfully understanding human speech, recognizie (识别)human faces, operate self-driving cars and compete in some game systems like playing Chess. However, Some people also consider(认为）AI a danger to humans if it develops too quickly. A famous British scientist also was not for this kind of technology.

    Math is the basic language of AI. If students are good at math, they will be more likely to become successful AI designers(设计者)in the future. We need not only bright students, but also average(普通的)students. As for(对于)average students ，if they get enough math skills, they can also become successful AI designers. Besides, a good knowledge of computer science is also necessary for AI designing.

    Scientists hope to create creative(有创造力)and emotional (有感情的)AI. The AI can possibly understand human feelings or create art. Many ways and tools have been tried to discover this wide and exciting field.