The Milu deer is a kind of animal with large horns(角). They were very common in China long ago. They lived together and ate grass and the soft parts of trees. In the past, people did not protect the Milu deer and killed them for food or sport, so they disappeared(消失) from China .

      Luckily before all of them disappeared, the Duke of Bedford(贝德福特公爵) took some to Britain. The Milu deer like the cool, wet weather in England and their numbers increased(增长) year by year. As a result, when in1985, the government of China wanted to bring back the Milu deer, the Duck of Bedford was able to help. The first deer came back to China to the Nanhaizi Milu park near Beijing and to Dafeng, Jiangsu Province.

      Since they returned to China, their number has grown quickly .There are now so many of them that a new park has been opened for them in Hubei Province. Now the Milu deer live in the wildlife parks and have good protection. We hope that one day they can live in the wild again.

    A recent study found people's lives are made shorter in North China. It is showed the life expectancy(平均寿命) had been cut down by 5.5 years there. Researchers（研究者）think that the heavy air pollution in China should be to blame(承担责任). It's really the truth. Our government has already done something. However, it doesn't seem to work so well.

    “Air pollution in China is doing harm to people's health. The harm is much more serious than we can imagine,” said Chen Yuyu of Beijing University, one of researchers of this study.

    Dirty air brings serious problems in North China. In January this year, the air pollution was worse than that in other places. That was caused by rising temperature and waste gas（气体）from coal heating（燃煤）.

    Chinese government should strongly fight with air pollution. They should think of more proper ways to deal with the problem. People should be encouraged to take buses, ride bicycles or walk, instead of driving cars. The factories that pollute heavily should be closed.

    “We need to improve our environment, although it might be expensive. Protecting our environment means protecting ourselves,” Li Hongbin, another researcher of the study said.

    Sheridan is a town in Indiana, USA. There are lots of trees near the public schools in the town. Their leaves turn sunlight into energy（能量）.

    In Sheridan, the sun not just provides energy for plants. It keeps schools running, too. The schools use solar panels（太阳能电池板） to turn sunlight into energy.

    The science behind solar energy is not new. But Sheridan Community Schools is the first school district(学区) in Indiana to be completely solar-powered. The district finished putting in solar panels for all three of its schools in 2016. Some of the panels can turn to follow the sun across the sky.

    In 2008, fewer than 1. 000 schools used solar power. By 2014, there were 3, 727 schools with solar panels in the USA. These numbers come from a report by the Solar Foundation. Roxie Brown, a program director there said that the number of schools with solar panels has continued to go up since 2014.

    Solar energy has some advantages over other energy sources(来源). Sunlight is a renewable source, which means it won't run out. Solar panels don't harm the environment. Also, sunlight is free. So by using solar power, schools can save money on energy costs.

    Brown thinks more schools should run on solar energy. "The sun is Earth s energy source," she says. "We're trying to make it the energy source for our houses cars and schools, too."

    But using solar energy isn't always easy. Solar panels can be expensive to put in. The panels also take up space. But for many schools, going solar is worth it.

    Life in space is much different from life on earth. How do astronauts live in space?

    Eating    In the past, astronauts could only eat small pieces of dried food. But now they are able to eat more everyday food like fruit, vegetables and ice-cream.

    Sleeping    All the people on the ISS（国际空间站）have their own rooms. They should be tied（系）to their beds, or they'll fly away! That seems like a hard way to sleep, but astronauts say sleeping is really not too bad.

    Exercising    This is more important in space than on earth. Astronauts exercise on bikes and other machines（机器）for about two hours every day. That way, they can still be healthy when they get back home.

    Having fun    Astronauts can read books, play cards, listen to music or send emails to their friends and families when they aren't working. Sometimes they just sit and look out of the window. It's also much fun!

    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.