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    With the development of Internet, relative services are developed in the form of websites or apps on phones too. Here introduces you Airbnb and Uber.

    1 Airbnb (air Bed and Breakfast)

People can offer or rent rooms for a short time on Airbnb website or its app on smart phones. The cost is usually cheaper than that of hotels. Travelers can book rooms with special activities such as enjoying local music, art and food.

    Airbnb was founded in August 2008, and now it has over two million listings for travelers to choose in the world. The idea of Airbnb, as its symbol shows, is about home and trust.

    2 Uber

    Uber is a ride sharing and taxi app for fast rides in minutes—day or night. It was founded as Uber Cab in March 2009. The Uber app can send an order to the nearest Uber driver, asking him to the location soon. Users can track the car on their smart phones, so they can know when it will arrive.

In August 2016, Uber service was provided in 507 cities and over 66 countries. However, in China, its operation was acquired by Didi in July 2016. The website Bloomberg View said in July 2015 that Uber makes it easier for people to get a taxi.

    Honey(蜂蜜）from African(非洲）forest is very delicious.

    Most people and many animals like eating it. However, the only way for them to get that honey is to find a wild bees' nest(蜂巢）and take honey from it. Often, these nests are high up in trees, and it is difficult to find them. But in parts of Africa, people and animals have a strange helper — a little bird called a honey helper.

    In fact, the honey helper does not like honey, but it likes the wax(蜂蜡）in the nest. The little bird cannot reach the wax because it is inside the bees' nest. So, when it finds a nest, it looks for someone to help. The little bird sings loudly to get the attention(注意） of both passing animals and people. When it has their attention, it flies through the forest, waiting for the following animal or person that loves honey. Then it helps them find the nest. When they finally arrive at the nest, the follower tries to get the delicious honey and the bird waits and watches. Some of the honey and the wax always fall to the ground, and this is when the bird takes its share.

    Scientists do not know why the bird likes eating the wax, but they seem to be able to smell the wax far away.

    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.

    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.

    Height is just one of the thousands of features your genes (基因) decide. In fact, because you have two parents, your genes provide you a height that usually lands somewhere between the height of each parent. If both your parents are tall, then maybe you will be tall, too, but if you have questions about how tall you're going to be, ask your doctor if he or she can help you find it.

    But genes don't decide everything. For example, eating an unhealthy diet can keep you from growing to your full potential (潜力). Getting enough sleep and enough exercise will help you grow to the right height.

    No doubt (怀疑) you're wondering how fast you should grow .It depends. There's no perfect or right answer. Kids grow about 2 inches (5 centimeters) a year between age 3 and the time when they start puberty (when your body starts changing and becoming more grown up). Your doctor will know how your growth has been going over the years. 2 centimeters here and 2 inches there are not nearly as important as the height you're at now, how you've been growing up to this point, and what other changes your body may be going through.

    Don't be scared if you seem to have grown a lot in a very short time. Everyone has a growth spurt (高峰) during puberty. The age for starting puberty is about 10 for girls and about II for boys. But it can be earlier or later-between 7 and 13 for girls and 9 and 15 for boys.

    You'll usually begin to notice that you're growing faster about a year or so after your body starts to show the first changes of puberty.