You may know a lot about smartphones. But what about smart cities?

Imagine living your life like this: When you wake up in the morning, you say "Open the window" to the computer and it opens the window. The sunshine is shining and the birds are singing. Then you finish breakfast and sit in front of your desk and begin to have classes through the Internet. With the help of building a smart city, this may become true one day.

A smart city uses digital technologies(数字科技）such as the Internet to improve city planning, save resources(资源) and make our lives easier. For example, people live in smart cities, where there is Internet almost everywhere. They can do many things at home, such as booking train tickets, paying water bills and shopping online. What a convenient life it is!

Now China is making some cities smarter. For example, Guiyang is going to build free Wi-Fi in the whole city. Tianjin plans to start a smart city program to solve traffic problems. Guangzhou is creating a smart city, so everyone in the city should play a role in creating a smart city.

    Here is some information about some of the wonders of the world. I am sure you will be interested in them.

    ThePyramids of Egypt

    There are about eighty pyramids known today. The most well-known was for Pharaoh（法老）

    Khufu. It is known as the "Great Pyramid". It's also the largest one. Workers used about 2.3 million blocks of stone to build it. They spent about 20 years finishing it.

    The Hanging Gardens of Babylon

    The garden sat on a hill. It was a large and wonderful structure（建筑物）. Many parts of the garden were high up on large columns（支柱）. There were many big and green trees with lovely flowers. Although there are many different ideas about the garden, we are not sure whether this wonder ever existed（存在）!

    TheLighthouse of Alexandria

    The Lighthouse of Alexandria was designed about 2,000 years ago. It was in Egypt, too. It was one of the ancient wonders of the world, about 135 metres high. It was once the highest building in the world. Although it doesn't exist now, many people come to see its relic（遗址）every year.

    I'm the engine that keeps you working, and I'm here to share some of my secrets.

    I have 100 billion nerve cells (神经细胞), so you need to consider before you blame (责怪) me for not being so fast enough. It's not really my fault: information travels through me too fast and sometimes I can't keep all of it.

    The Internet is making me weak. A study found that you've been relying more on the Internet. That means I'm going to forget more over time. Scientists have been worried that our ability to think is being lost.

    In general, I'm about ten percent larger in men than women. It doesn't make men smarter. It just lets me control their different bodies. Actually, it's more common for women to get angry, but men can't focus on a thing well. They usually have language difficulties.

    Your mobile phone scares me. A new study showed that more than one hour of mobile phone use can get me in trouble. Mobile phone radiation (辐射) might cause me to be in a worse situation.

    Some parts of me never sleep. It's important for you to get a good night's sleep. Sleep helps to improve memories. In fact, when you are asleep, some parts of me are still working hard on my duty.

    Besides, laughter is really the best medicine for me. So remember to laugh more for my better situation.

    In today's world, almost everyone knows that air pollution and water pollution are harmful to people. However, not all the persons know that noise is also a kind of pollution, and that is harmful to human, too.

    People who work and live under noisy conditions usually become deaf(聋的). Today, however, scientists believe that 10 percent (百分比) of workers in Britain are being deafened by the noise where they work. Many of the workers who print newspapers and books, and who weave(织) cloth become deaf. Quite a few people living near airports also become deaf. Recently(近来) it was discovered that many teenagers in America could hear no better than 65-year-old people, for these young people like to listen to "pop" music and most of "pop" music is a kind of noise. Besides(除此之外), noise produced by jet planes or machines will make people's life difficult and unpleasant, or even make people ill or even drive them mad.

    Nowadays the government in many countries have made laws to reduce or control(控制) noise and make it less than 85 decibels(分贝).  In China, the people's government is trying to solve not only air and water pollution problems but also noise pollution problem.