阅读下面材料，从每题所给的三个选项（A、B和C）中，选出最佳选项。

Invention 1	These glasses are made from a special liquid(液体). They allow users to adjust the focus(调整焦距) of the glasses until everything is clear. They are designed for children. So they won't buy new glasses every time when their eyesight changes.
Invention 2	The Donkey Bike has a strong steel bar(钢条) running along it. It can carry both a gas can and a pet at the same time when you ride this bike.
Invention 3	This machine looks friendly and is called Little Printer. It can print news headlines, riddles and other things on a roll(卷) of paper. So you can make your own little newspaper with it.

Making Music with Water

     Have you ever tried making music with glasses or bottles filled with water? I bet your favorite band hasn't. Experiment with your own special sounds by turning glasses of water into instruments, make some cool music and find out how it works.

     What you'll need:

     Five or more drinking glasses or glass bottles.

     Water.

     Wooden stick such as a pencil.

     Instructions:

     Line the glasses up next to each other and fill them with different amounts of water. The first should have just a little water while the last should be almost full, and the ones in between should have slightly more than the first.

     Hit the glass with the least amount of water and watch the sound, then hit the glass with the most water, which makes the higher sound?

     Hit the other glasses and see what noise they make. See if you can get a tune going by hitting the glasses in a certain order.

     What's happening?

     Each of the glasses will have a different tone when you hit with the pencil. The glass with the most water will have the lowest tone while the glass with the least water will have the highest. Small vibrations are made when you hit the glass, and this creates sound waves which travel through the water. More water means slower vibrations and a deeper tone.

C

    In England, people often talk about the weather because they can experience (经历) four seasons in one day. In the morning the weather is warm just like in spring. An hour later black clouds come and then it rains hard. The weather gets a little cold. In the late afternoon the sky will be sunny, the sun will begin to shine, and it will be like in summer at this time of a day.

    In England, people can also have summer in winter, or have winter in summer. So in winter they can swim sometimes, and in summer sometimes they should take warm clothes.

    When you go to England, you will see that some English people usually take an umbrella (伞) or a raincoat with them on a sunny morning, but you should not laugh at them. If you don't take an umbrella or a raincoat, you will probably regret (后悔).

    Artificial intelligence (AI) (人工智能）is the ability of a computer program or a machine to think and learn. It is also a field of study that tries to make computers "smart". John McCarthy, a scientist, came up with the name "artificial intelligence" in 1955. Many things such as learning and problem solving can be done by computers, though not in the same way as we do.

    An unusual goal of AI research is to create computer programs that can learn, solve problems, and think logically(逻辑地）. At present we use the term Al for successfully understanding human speech, recognizing(识别）human faces, operating self-driving cars and competing in some game systems like Chess and AlphGo（阿尔法狗）. Some people also consider AI a danger to humans if it develops too quickly. Professor Stephen Hawking (霍金), a well-known British scientist, was not for this kind of technology.

    Math is the basic language of AI. If we raise the standard in the learning of math, our students will be more likely to become successful AI designers in the future. We not only want bright students, but also need to attract average students and give them the math skills which are needed to change them into AI designers. Besides, a good knowledge of computer science is also necessary for AI designing.

    Scientists hope to create creative and emotional AI which can possibly understand human feelings or create art. Many ways and tools have been tried to discover this fascinating field.

    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.