In 1826, a Frenchman named Niepce needed pictures for his business .But he was not a good artist .So he invented a very simple camera. He put it in a window of his house and took a picture of his garden .That was the first photo.

    The next important date in the history of photography was in 1837. That year, Daguerre, another Frenchman, took a picture of his reading room .He used a new kind of camera in a different way. In his picture you could see everything very clearly, even the smallest thing. This kind of photo was called a Daguerreotype.

    Soon, other people began to use Daguerre's way. Travelers brought back wonderful photos from all around the world .people took picture of famous buildings, cities and mountains.

    In about 1840, photography was improved .Then photographers could take pictures of people and moving things .That was not simple .The photographers had to carry a lot of films and other machines. But this did not stop them, for example, some in the United States worked so hard. Mathew Brady was a famous American photographer. He took many pictures of great people .The pictures were unusual because they were very lifelike.

    Photographers also became one kind of art by the end of the 19th century. Some photos were not just copies of the real world .They showed feelings like other kinds of art.

    We all cry for water when we are thirsty. But do you know, in very hot, dry weather, plants also make very low sounds as if they are crying for help?

    You see, in a plant's stem there are several hundred "water pipes" that bring water from soil all the way up to the leaves. When the ground turns dry, it becomes harder and harder for plants to do this.

    On very hot days, plants have to get any water that they can get.

    Scientist Robot Winter has found out that when plants can get no water, their "water pipes" snap(发出声音). When that happens, the whole plant vibrates(振动) a little.

    Robot knows that healthy, well-watered plants are quiet.  He also knows that dry plants are many insects' "favourite" and they often attack(袭击) them. How do the insects know which are healthy plants and which are not? Robot thinks that the insects may hear the plants "crying" and they may come to kill them.

    Imagine a world with no more animals: no elephants, no tigers or lions. To some people, that thought is too terrible for words. So they are doing something about it. Tiffany Soechting is one of them.

    Being among wild animals—feeding them and caring for them—is all Tiffany Soechting has wanted to do with her life. And that is exactly what she does!

    Soechting is the human "mother" to the 500 animals that live on her family wildlife farm in San Antonio, Texas. On the farm, she cares for animals from around the world. Soechting says she loves them all. However, two reticulated giraffes(网纹长颈鹿) take up a special place in her heart. Their population in the wild has become smaller by 80% in the last 15 years. "I'm so glad to get help from five wildlife researchers that took giraffes up to a higher level. All our hard work helps protect giraffes living in the wild."

    Besides her animal caring, Soechting also holds monthly classes, where she teaches school children about the animals.

    Soechting also opens the farm to the public. Visitors not only learn about the animals, they can also get close to them. And the animals are not against that. For them, people are part of their natural environment.

The farm is part conservation(保护) area, part educational center and part animal park. As the animals walk peacefully around the grounds, it is easy for them to forget that San Antonio, a busy city, is just a few minutes away.

    Robots come in many shapes and sizes. But most have one thing in common. They are built to help people, Lately engineers have been developing new kinds of robots. These high-tech machines are designed to lend a hand everywhere from hotels to disaster areas.

    "Robots help people by making their lives easier, safer, and more fun, "says engineer Omar.

    Since November, a robot named Pepper has been on the job at Mandarin Oriental Hotel in Las Vegas, Nevada. When guests have questions or need directions, they can ask Pepper. They can also use the robot's touch screen to find the information they need. Pepper is able to talk with guests and make them happy with stories too. It can even tell what kind of mood they are in.

    "Pepper provides our guests with information in an exciting and new way." says the hotel manager Donald Bowman.

    For a kid, being in the hospital can be boring and even scary. But a small robot called NAO is helping to make hospital stays easier. It was designed to keep people company.

    A Tennessee doctor named Phil Parker bought a NAO robot three years ago. He programmed(为…….编制程序)it to talk to and play with young patients. He brought it to hospitals to help sick kids. When kids get medical tests, NAO explains what is going on. The robot also reads to kids and plays games with them like Rock, Scissors ,Cloth(石头剪刀布).

    "The robot gets many kids to smile for the first time since they were in hospital," Parker says.

    Other robots are designed to help to save people in dangerous areas. For example, disaster areas can be full of broken stones and other dangers. Engineers in Japan are planning to build a robot called E2-DR to go into those areas and search for people who are hurt.

    I'm sure you all know how important recycling is. Recycling is when you take old things and turn them into new things. It sounds like magic. But it's actually very scientific.

    If you had billions of dollars, would you donate almost all of it to charity? Well, that's what Mark Zuckerburg, CEO and founder of Facebook, just said he would do.
    Zuckerburg and his wife Priscilla Chan promised to give 90% of their Facebook shares to society. Right now that is about $45 billion, and they plan to donate the money to things like science and education.
    Many billionaires have done similar things. Bill Gates, creator of Microsoft, made The Giving Pledge, an activity in which billionaires promise donate more than half of their wealth to charities. This started in 2010, and now 139 people from 15 countries joined it.
    But giving back and helping others isn't just for big billionaires. People like Zuckerberg, and Gates may have more to give, but people with less are doing it, too.
    Especially around the holidays, people want to do their part and give back to people who are less lucky than them. Schools may have food collections where people bring a few food items, and together they can make a big donation to places like homeless people's homes.
    People also host special events like concerts of runs to be creative while raising money. Regular people donate whatever they can to US charities like the United Way and the American Red Cross.
    Then these charities are able to help US communities in different ways like education, health and improving the lives of the poor. These individual donations come together to make a big difference.