阅读下面四篇短文，从每题所给的A、B、C、D四个选项中选出最佳选项。

C

    Indian scientists have designed a new device that they hope will solve one of the biggest problems with the use of solar energy. They call the device a solar tree. Solar trees have metal “branches” which are just from a tall pole at different levels. Each branch holds a solar panel*. These panels have large metal boards that collect energy from the sun and turn it into electricity.

    Daljit Singh Bedi is the main scientist at the Council of Scientific and Industrial Research in India. Bedi says the shape of the solar trees makes it possible to fit more solar panels in a space than traditional systems do. This means less land would be needed to produce solar energy. “It takes about four square meters of space to produce energy which may need 400 square meters of space,” he says.

     Scientists believe the energy a solar tree collects will be enough to power five homes. The solar tree will make it easier to provide solar energy for homes in cities. The trees will also take less space from farmers in rural areas. Bedi says solar trees will collect more energy than normal solar panels on the tops of buildings. “This design makes the solar panels exposed more towards the sun,” he says. “And that way people are able to use 10 to 15 percent more energy.”

    India has promised to reduce its greenhouse gas production. The country's promise depends heavily on increasing solar energy. The cost of solar panels has gone down in recent years. This has increased the possibility of applying solar trees in India.

    Amit Kumar is the senior director of the Energy and Resources Institute in New Delhi. He says gaining access to land takes time and increases costs. He adds that it is still not clear how useful these new developments in solar power technology are. “Only when we put those trees on a large scale will we be able to get that answer,” he says.

    Anyone who has had a long-term illness knows that recovering at home can be boring. This can be especially true for children. They may feel cut off from their friends and classmates. Now, these children may have a high-tech friend to help feel less lonely. That friend is a robot.

    The robot is called Avatarl (AV1). It takes their place at school. Through the robot, the children can hear their teachers and friends. They can also take part in classes from wherever they are recovering. And the children's school friends must help. They carry the robot between classes and place the robot in the classroom.

    A Norwegian(挪威的) company called “No Isolation” created the robot. There are another two co-founders, Karen Dolva and Marious Aabel. Dolva explains how the robot works. She says from home the child uses an iPad or a phone to start it, control the robot's movements with touch and talk through it. The child can take part in classroom activities. The robot is equipped with speakers, microphones and cameras that make communication easy. So it's the eyes, the ears and the voice of the child at school. Inside AV1 there is a small computer connected to a 4G network.

    AV1 is designed to be tough. It won't allow water to pass through it and can take a fall from a desk without damage. AV1 is large and looks like a human for a reason. Dolva says it can't be just a tiny camera because the other kids can't pick it up and take it with them. This is important because the robot is supposed to be a friend to the children. Hopefully AV1 will help some children feel less lonely while they were absent from class.

    You don't need to get in a time-travelling machine to see how technology will change our lives, such as the way we shop. Several new technologies that are to change your buying habits already appear. Let's see what's in store for your future shopping.

    Try it on, virtually(虚拟地). Want to shop online for a new pair of glasses? You don't need to guess which pair looks best on you—use the eBay Fashion iPhone app to try a pair of glasses you're checking out on a picture of your face. But what about buying something bigger? Thanks to Microsoft Kinect's action tracking(跟踪)camera, you can cover clothes on your screen body. You can even choose the background of your virtual fitting room to improve your shopping experience.

    Get a perfect, custom fit. Everyone's body is shaped differently. To get a perfect fit, you sometimes have to get your clothes changed. But by using 3D scanning technology, all the clothes you buy will fit your body perfectly. Some companies scan(扫描)your body using High-tech to get the real sizes, so they can make special clothes just for you.

    High-tech shopping carts(推车)and checkout counters(收银台). High-tech shopping carts could be common in malls and supermarkets in the future. Microsoft Kinect-enabled carts are under test. The cart can follow you along the aisles(通道), controlled only by your movement and your voice.

    In the United States, several supermarkets use a certain set called "Scan It" that gives buyers the freedom to scan products on their own while they shop. If we don't want to wait in line before the checkout counters, we can use Toshiba's new object Recognition Scanner. The machine identifies(辨认)a product as soon as it's placed in front of a camera just by its shape and color, even if it has no bar code.

    Now, it seems that artificial intelligence(人工智能) is becoming more and more popular in our life, and it has greatly influenced the ways we live, work and play. Can you imagine that you can play table tennis with a robot one day?

    Recently, a scientist has invented a special robot that can be a table tennis coach. That means people can practice table tennis not only with humans but also with a robot.

    Named Forpheus, the smart table tennis robot is quite special. It can study the movements of human players and the speeds of the ball. In this way, it can exactly judge(判断) the players' skill levels(水平).Then it uses the information to change the ways to play. If the players are just beginners, Forpheus will play in a slow and easy way, but if the players are better ones, the robot will play in a faster and more difficult way. What's more，while playing, it encourages players 10 try their best with words like "Good job!" "Come on!" and so on. At the same time, it gives some good advice to improve their sill so it is a good partner and clever coach.

    Science and technology is developing quickly these days and it's hard to imagine what will happen in the future." In the next 20 years, it will be possible that one robot teaches another to play table tennis or even invents another one!" Takuoya, the inventor of the robot, said.