In 1969, humans landed on the moon for the first time. Now, many other countries want to go there as well. Why?

    The moon has a lot of minerals (矿物质) and other useful things. We want to find out if we can use them. The moon is our closest neighbor in space. We can use it as a rest station. Then, we can learn more about other planets far away in space.

    The moon is 3,474 kilometers in diameter (直径). It is about one-fourth the size of Earth. If Earth is the size of a basketball, the moon is the size of a tennis ball.

    The moon has much less gravity than Earth. If you can jump 1.5 meters on Earth, you can jump 9 meters on the moon.

    The moon is very quiet. There is no sound there. There are a lot of grey rocks on it. The moon's sky is always black.

    Our moon is about 384,400 kilometers away from Earth. The total length of the Great Wall is about 21,200 kilometers. We would have to put about ____ Great Walls end to end to reach the moon!

    Researchers have developed paper that can be printed with UV light (紫外线), free from the need for ink (油墨). People can clear the information away on the light-printable paper by heating it to 120℃and it can be reused more than 80 times.

    The research was carried out in order to reduce the effects of paper production on deforestation (滥砍滥伐). The researchers, from Shandong University in China and the University of California, Riverside, said that the secret behind the technology is a color-changing chemical. A thin coating of the chemical can be used on usual paper and turn it into a reusable, light-printable one. Heating the paper for 10 minutes can help clear the information away more quickly.

    Professor Yadong Yin, a chemistry professor at the University of California and a co-author of the study, said, "The greatest importance of our work is the development of a new technology to produce an ink-free rewritable paper that has the same feel and appearance as usual paper. Our work is believed to have great economic and environmental influences on the modem society." Paper production has a bad influence on the environment. It's the main cause of industrial pollution and paper thrown away by people makes up about 40% of landfills where waste is buried under the ground.

    It is predicted that light-printable paper will be inexpensive in the future. The printing process is also more cost-effective than the usual one as no ink is needed. Most importantly, it can be reused many times, which greatly reduces the cost.

    Uber (优步)announced that it plans to invest 20 million in developing an aircraft in France over the next five years.

    It will open a new research and development center in Paris﹣its first technology hub outside of North America.

    "France is a perfect home for our next step forward with its strong history of research and development, world class engineers and a unique role in aviation (航空)worldwide,"Uber said in a statement.

    Uber already has R & D offices in Pittsburgh, Toronto, and San Francisco. They focus mainly on Uber's self﹣driving technology, but have also been working on Uber's Elevate flying car program.

    The Advanced Technologies Center in Paris will open later this year and only focus on flying cars. It will conduct research into airspace management, real﹣time communication networks, energy storage, and charging systems.

    Uber's announcement, made at a tech meeting in Paris, has been supported by French President Emanuel Macron, whose ambitious economic reforms are to attract more foreign investment.

    The company also announced a five-year research partnership with Ecole Polytechnique, a leading French institute of technology.

    Uber has been working on its flying car program since 2016. NASA became a partner for the program a year later by developing air traffic management for a fleet of flying cars.

    Uber expects flight to become a daily part of our transportation lives. The company believes it can offer rides in flying cars for about the same price as an Uber X ride. This technology may completely change our transportation lives in the future.

    What will man be like in the future-in 5. 000 or even 50, 000 years from now？We can only make a guess, of course, but we can be sure that he will be different from what he is today. For man is slowly changing all the time. Now look at the chart below, and you'll find some differences.

    Perhaps all this gives the impression that future man will not be a very attractive creature(生物) to look at！This may well be true. All the same, in spite of all these changes, future man will still have a lot in common with us. He will still be a human being, with thoughts and emotions(情感) similar to our owns.

    Would you like to go to the zoo at night? Last month, Shanghai Wild Animal Park opened its night safari(夜间观赏)for the first time. You can see animals in the dark. Some animals enjoy the night—they are nocturnal(夜行的)animals. Who are they?

    The coffee shop Starbucks will give people a discount if they bring their own cups. It wants to cut down on the number of paper cups that are put in the rubbish bins. It is part of a two-month experiment in cafes in England. Starbucks wants to reduce waste and recycle more, The president of Starbucks in the UK said, "We are very happy to increase recycling rates(比率)，and reusable cups are a key part of our waste reduction plan." Bosses will decide later if they will continue the discounts. People who bring their own cups will not get a discount on the cafe's cheaper filter coffee.

    The problem of paper cups has been in the news a lot. Around seven million cups are thrown away every day. Reporters say that some cafes lie about how many paper cups they recycle. The reporters say the cafes do not recycle as many cups as they say. Customers wrongly believe that a coffee shop is environmentally friendly. Less than one in 400 paper cups at coffee shops are recycled. A coffee drinker said she would bring her own cup. She said, "I am so sad that cafes recycle so little. I thought they were more responsible."