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    In nature，you may see many insects and animals of different colors．Have you ever wondered why?

Locusts(蝗虫)are super delicious food for birds，but it is not always an easy job for birds to catch them．It is neither because locusts are good jumpers or runners nor because they are smarter than their enemies．The reason is that the colors of locusts change with the colors of crops(农作物)．When crops are young，locusts look green．But when autumn comes，locusts change to the yellow and brown color as crops do．

    Brown bears，tigers and other animals move quietly through forests．They can't be seen easily by their enemies．This is because they have colors similar to the trees．For the same reason．polar bears that live on a land of snow and ice are white．Butterflies and bees living among the flowers are colorful like flowers．Soil insects are mostly dark—colored and they live under the soil in a dark and wet environment．However，insects with colors different from plants can easily be found and eaten by others．So in order to survive ， they have to hide themselves in the daytime and appear only at night．

    Have you ever noticed some even stranger acts? The ink fish in the sea can send out some very black ink when it faces danger．As the ink spreads over．its enemies will not find themselves suddenly in a dark world．At the same time the ink fish immediately swims away．That is how it keeps itself save though it is not strong at all．

    To protect the environment, we are on the way. Here are a few things we can do.

    Unwanted gifts? Give them away!

    Have you ever received a gift that you didn't like? Did you throw it away? If so, you can have another choice now. Two British companies hopes people will give away their unwanted gifts to them. And they will resell the gifts to raise money for the poor. In this way, the gifts can be refused and have a future life. And people can make a difference to the world.

    Wear the trousers that reduce(减少) pollution!

    A chemistry scientist and a fashion designer(时装设计师) have created a new kind of trousers. The trousers are made of a new material which can help reduce air pollution around us. Scientists have tested the material. The result shows that it isn't harmful to human. This new kind of trousers may appear at the market in two years. Professor Ryan said, "If thousands of people wear the trousers, the air quality will be improved."

    Plant trees with Felix

    Felix Finkbeiner, a 14-year-old German boy, is not famous as a child actor but an environment hero. At the age of 9, Felix got the idea that children could do something to protect the environment. So he started a club. Felix soon got support from children all over the world. Some of them have become his good friends. The club has an aim of planting 212 million trees. They have planted over 3.5 million trees all around the world. Felix said, "The answer to controlling global (全球的 ) warming is trees-lots of trees!”

New App Helps People Remember Faces

    Large gatherings such as weddings and meetings can be socially Q flooded with people. Learning people's names only adds to the stress. A new facial-recognition app could come to the rescue, but experts suggest people should be careful while using it.

    The app, called SocialRecall, connects names with faces through smartphone cameras and facial recognition, avoiding the need for formal introductions. "It breaks down these social barriers we all have when meeting somebody, "says Barry Sandrew, who created the app and tested it at an event attended by about 1, 000 people.

    After receiving an invitation to download SocialRecall from an event organizer, the user is asked to take two selfies and sign in through social media. At the event, the app is active within a previously set geographical area. When a user points his or her phone camera at an attendee's face, the app identifies the person, displays the person's name, and links to his or her social media information. To protect Privacy, it recognizes only those who have agreed to use. And the app's creators say it automatically removes users' data after an event.

    Ann Cavoukian, a expert who runs the Privacy by Design Center of Excellence praises the app's creators for these protective measures. She added, however, that when people choose to share their personal information with the app, they should know that "there may be unexpected results down the road with that information being used in another situation that might come back to bite you."

    The start-up project has developed the app for people who suffer from prosopagnosia, or "face blindness, "a condition that prevents people from recognizing people they have met. To use this app, a person first receives an image of someone's face, from either the smartphone's camera or a photograph, and then tags it with a name. When the camera spots or recognizes that same face in real life, the previously entered information is displayed. The collected data are stored only on a user's phone, according to the team behind the app.

Man first walked on the moon 55 years ago. Now we are still {#blank#}1{#/blank#} (梦想) of living in space.

We learn from the {#blank#}2{#/blank#}(新闻;消息) that a US company is building a space hotel—The Von Braun Station. It looks like a wheel(车轮) from the outside and as many as 400 people can live in it. So what will the hotel be like {#blank#}3{#/blank#}(在里面)? In some ways, it is just like {#blank#}4{#/blank#}(普通的) hotels on the earth. People can have a drink in bars while enjoying the {#blank#}5{#/blank#}(宇宙). But living in such a hotel is still {#blank#}6{#/blank#}(不可能的) at the moment. It's said that the company plans to complete the {#blank#}7{#/blank#} (项目) by 2025 and open it to the public by 2027. And space travel is {#blank#}8{#/blank#} (昂贵的). One person will spend 250,000 dollars {#blank#}9{#/blank#} (到达;抵达) the hotel. And the {#blank#}10{#/blank#}(价钱;成本) of staying in the hotel will be 9.5 million dollars.

A tornado (龙卷风) is a kind of strong storm with air which moves in a circle quickly. They can move over 200 miles per hour and cause a lot of damage. As they move across the land, they can easily pick up cars, trucks, and even houses, and then throw them very far. It is important to find a safe place if a tornado gets close. 

A safe place could be a basement or the lowest floor. If you are in a home without a basement, try to find a first-floor bathroom or a small room without windows in the middle of your house. You should curl up (蜷缩) into a ball and cover your head and neck with your hands. 

But there are some people who actually want to get close to tornadoes. They are scientists who want to learn more about tornadoes. One of the best ways to do this is to get as close as possible to the tornado. They use special tools to measure (测量) what is happening in and around a tornado. 

One special tool is called a tornado probe (探测仪) . Inside the tornado probe, there are sensors (传感器) to measure wind speed, temperature, pressure, and direction. Some probes even have cameras, so the scientists can see and understand what it's like to be in a tornado.

To be able to get these measurements, the scientists have to get a tornado probe near or into a tornado. Scientists will try to guess where a tornado will go next. Then they drive to that location and put down the probe. If they do not guess correctly, they pick up their probe and r another place. If they are right, the tornado will go near or even right over the probe. Then they take all of the measurements from the probe and use them to predict where future tornadoes may form and travel. And they can give people some warning to keep away from a dangerous tornado.