We humans live in different parts of the world, but we have the same “mother”. She gives us everything we need in our daily life. She is our Mother Earth.
    April 22 is Earth Day. The theme of this year is “Green Cities”.
    A green city is a healthy and pleasant place for people to live, according to the United Nations.
     A green city can get its energy from renewable (可再生的) sources like solar (太阳能的) and wind power. Also, it is connected by clean public transportation. Moreover, a green city is made up of facilities (设施) that can save energy and reduce waste.
Around the world, many cities and countries have done well to build themselves in a green way.
     Chicago is well known for its green roof (屋顶) program. These roofs are covered with plants. The plants get a great amount of rainwater. Later, the water evaporates (蒸发) to help make the air cool and clean. So far, there are about 360 green roofs in Chicago, according to the US Environmental Protection Agency.
      Curitiba, Brazil, has great transportation. It opened the world's first bus rapid transit (BRT) system in 1974. BRT runs on special lanes. This makes sure that buses are on time even in traffic jams. With the help of BRT, the city has the lowest level of air pollution in Brazil. Today, many other countries have copied BRT, including China and Mexico.
      Singapore is home to the first zero-energy building in Southeast Asia. Zero energy means a building is able to create more energy than it uses. Zero-energy buildings work with solar panels (板) mainly on roofs. These panels can make electricity which powers the buildings. By 2030, Singapore plans to build 80 percent of its buildings like this.

   About 21,000 young people in 17 American states do not attend classes in school buildings.
   Instead, they receive their elementary and high school education by working at home on computers. The center for Education Reform says the United States has 67 public “cyberschools(网络学校)” and that is about twice as many as two years ago.
   The money for students to go to a cyberschool comes from the governments of the states where they live. Some educators say cyberschools receive money that should support traditional public schools. They also say it is difficult to know if students are learning well.
Other educators praise this new form of education for letting students work at their own speed. These people say cyberschools help students who were unhappy or unsuccessful in traditional schools. They say learning at home by computer ends long bus rides for children who live far from school.
   Whatever the judgment of cyberschools, they are getting more and more popular. For example, a new cyberschools called Commonwealth Connections Academy will take in students this fall. It will serve children in the state of Pennsylvania from ages five through thirteen.
Children get free equipment for their online education. This includes a computer, a printer, books and technical services. Parents and students talk with teachers by telephone or by sending emails through their computers when necessary.
   Students at cyberschools usually do not know one another. But 56 such students finished studies at Western Pennsylvania Cyber Charter School recently met for the first time. They were guests of honor at their graduation.

— Yes, _______.