Over millions of years ago, there were no deserts. Now about three tenths of the Earth's surface deserts. The size of the world's deserts is always (change). Deserts can be hot or cold. The Australian Desert is a hot desert, while the Gobi Desert in Mongolia is an example of a cold desert. Deserts are dry areas less than 50 cm of rain falls each year. The Sahara Desert in Africa receives less than 1.5 cm a year. rain doesn't fall very often in deserts, sometimes even for years, there can be heavy rain (sudden). Because they are dry, deserts have wide changes in temperature each day. When the sun (go) up, it is very hot. At night, the heat (receive) by the ground during the day (quick) disappears (消失), and then it becomes very cold. Becausethe change, living in the desert is very difficult. Man can make deserts, but they can also stop them from getting larger and larger. Planting trees can prevent the sand from(spread).
Many people want to know about the UFO. Do you 1 there are UFOs in the world? Some people do. They say they have seen one with their own eyes. James Green is one of them. He had a very unusual 2 on October 2, 2010. "It's too strange!" he said.
That day, he 3 his bike to the countryside. He wanted to play with some friends. They all arrived there on time. Then they began to play games. 4 for James, he didn't feel well after some time. 5 he went back home alone. On the way, he passed by a factory. He saw two white lights shining 6over the chimney(烟囱) of the factory. He felt 7 because he never saw such things before. So he got off his bike. He went up for a closer 8 . He could see a twenty-foot-long cigar-shaped object. Each end had a white light, and it moved over the chimney. After a while it made a light sound and 9its lights. So he couldn't see it.
That night, a woman reported the UFO to the police. And the police station received many 10. However, they wouldn't say the names of the callers.
Ender Wiggin is a 6-year-old army general(将军), and a gaming genius（天才). Sometime in Earth's future, humans will have a war with bug-like alien species, the "Buggers". They use computers to control battles(战争).To prepare for the war, all talented children study in a special school to become generals. Wiggin is one of them.
Students play games to practise their commanding (指挥的) skills. Wiggin is the best of them. At last, Wiggin comes to his final test. The fleet(舰队) he commands in the game is the real human army. Wiggin is actually "playing" the final battle between humans and Buggers. Will he win? What will happen to humans after the battle? Let's find out in the book Ender's Game, by the American writer Orson Scott Card.
After watching the movie The X-Files, Kelly and, her friends start to discuss whether aliens are real or not.
Stacy believes that aliens are real and they are living right among us. They wear human skin and act like humans. In her opinion, aliens want to take over the Earth and kill all human beings.
Alicia says that the government knows all about aliens. They are here to kidnap humans and do experiments to find cures for illnesses and help end global warming!
"My girls," says Kelly, "you have so much imagination!" She adds, "There are no aliens and what you read about in the newspapers is just a gimmick(噱头) to make people buy the newspapers. The X-Files is just a film which gives the director full space for his imagination. "Kelly then stands up and goes to the washroom.
Kelly locks the washroom door behind her. She looks at herself in the mirror and thinks they will never know who she is. "I must find the mother ship and go back to the planet," she thinks.
