When George was thirty-five, he bought a small plane and learned to fly it. He soon became very good at it and made his plane do ①all kinds of tricks.

    George had a friend. His name was Mark. One day George wanted to take Mark up in his plane. Mark thought, "I've traveled in a big plane several times, but I've never been in a small one. So I'll do."

    They went up, and George flew around for half an hour and did all kind sof tricks in the air.

    When they came down again, Mark was very glad to be back ②safely, and he said to his friend in a shaking (颤抖的)voice ,"Well ,George, thank you very much for those two trips in your plane."

    George was very surprised and said, "Two trips?"

    "Yes, my first and my last," answered Mark.

Information Card

    Vienna is a beautiful old city on the River Danube in the center of Europe. It's the capital city of Austria and the center of European classical music. In the 18th century a lot of musicians came to study and work in Vienna.

    In the Strauss family, there were two composers called Johann Strauss: the father and the son. The father, Johann Strauss the elder, wrote and played music for traditional dances, called the waltz. His dance music made him famous all over Europe. The son, Johann Strauss the younger, was also very successful and popular. He wrote over 150 waltzes. In 1867 he wrote The Blue Danube waltz.

    Mozart was another very important composer. He was born in Austria in 1756. Before he was six, he played not only the piano but also the violin. His family took him around Europe and he gave concerts in many cities. He wrote hundreds of wonderful pieces of music. But he became very poor and died in 1791 when he was only 35. Like Johann Strauss, father and son, he was a great European musician, and many people still think his music is perfect.

    Many people know that rubbish is a big problem on planet Earth. What many people don't know is that junk (垃圾) has become a problem in outer space too.

    According to BBC News, there are more than 22, 000 pieces of space junk floating around the earth. And these are just the things that we can see from the surface of the earth by telescopes (望远镜). There are also millions of smaller pieces of junk that we can't see.

    Objects, like bits of old space rockets or satellites, move around the planet at very high speeds, so fast that even a very small piece can break important satellites or become dangerous to astronauts. If the tiniest piece of junk crashed into a spaceship, it could damage the vehicle.

    To make things worse, when two objects in space crash, they break into many smaller pieces. For example, when a U. S. satellite hit an old Russian rocket in 2009, it broke into more than 2,000 pieces, increasing the amount of space junk.

    To reduce additional space junk, countries have agreed that all new space tools can only stay in space for 25 years at most. Each tool must be built to fall safely into the earth's atmosphere after that time. In the upper parts of the atmosphere, it will burn up.

    Many scientists are also suggesting different ways to clean up space junk. In England scientists are testing a metal net that can be fired into space junk. The net catches the junk and then pulls it into the earth's atmosphere to burn up. The Germans are building robots that can collect pieces of space junk and bring them back to Earth to be safely destroyed.

    "The problem is becoming more challenging because we're sending more objects into space to help people use their mobile phones and computers," says Marco Castronuovo, an Italian space researcher.

    "The time to act is now. The longer we leave the problem, the bigger it will become," he says.