In the past, different countries used different ways to communicate. In Africa, people used drums (鼓) to send messages to different places. In China, on the Great Wall, people used smoke or fire to send     1    . In some countries like the USA and Russia, horses were used to carry messages. Pigeons and other birds with special skills for     2     their way were also used.

Of course, only simple messages could be sent     3     these ways. In 1837, people began to use the telegraph (电报) to send longer letters. One of the most     4     inventions (发 明) for communication, the telephone, was invented by Alexander Graham Bell a few years later and phone lines (线) have been carrying our messages around the world for over 100 years. Today we can send text messages to our friends and even     5     with people in other areas. Communication was never this easy before!

Inventions always play an important role in our     1     life. They make our life wonderful and much easier.

A teacher in Harvard University wanted to let his students do a     2    . So he said to the class, “I want you to solve a world problem about electric energy. Who can finish the task?”

    3     hearing that, Julia and Jessica answered, “We want to accept this difficult work.” They thought they should     4     a research first in order to finish the task well. So they     5     some countries with less electric energy on the paper and studied them carefully.

They noticed that people in these countries played soccer. So Julia and Jessica worked with friends to design a soccer ball with a battery(电池) in it. Though they had an idea, it was a bit hard for     6     to make it come true. Then they asked their friends     7     help. It took them a long time to complete the task, but finally they did it     8    .

Julia and Jessica named their ball the SOCKET. When the players kicked(踢) the ball, the battery inside caught the energy from the     9     movements. After games, the players used the energy in the battery to power LED lights and phones. It is fantastic that a simple class project can make our lives much     10    .