阅读下列短文，从每题所给的四个选项（A、B、C和D）中选出最佳选项。

    Jogging is good for us and helps us live longer and healthier. It's easy to do and free. You do not have to spend money jogging. You can do it in a park or even in your home. But many people find it boring after jogging for a while. Then how can we keep jogging fun? Here are some ideas to make your jogging more interesting.

    First, you should choose to wear your favourite sports clothes and shoes when you jog. They make you more comfortable and more likely to run.

    Always jog outdoors. By changing your route, you can choose another street, and you will always have something interesting to enjoy when you jog.

Take along with your MP3 player and listen to your favourite songs when you jog. The music can make you excited and run farther without feeling bored.

    It's always more enjoyable with a friend. Make friends while jogging. Join a running club, find a new running partner, or invite an old friend to go jogging. It's better to find a friend who runs a little faster than you. Then you can try to catch up with him or her.

    Have you ever seen a car without a driver? It sounds crazy, but these computer-driven driverless cars will soon be filling roads near you. Companies like Google and Tesla have been designing and testing these cars, and the technology is there.

    So how? The cars have sensors（感应器）all around which can find other cars and objects in the road. Road signs are read by cameras, and satellite navigation systems（卫星导航系统）are used so the car knows how to get where you want to go. All you have to do is type in the address! Finally, a central computer system takes in all the information that it receives from the sensors and cameras and works out when to speed up, stop and turn.

    Sound like your idea of heaven（天堂）? Sitting back, looking out of the windows and even watching a film or reading a book while ‘driving' would be possible with this new technology. You wouldn't have to worry about remembering directions to where you're going. In addition, computers would also drive more safely than people — they would obey the rules and have quicker action times when in dangerous situations.

However, there are many drawbacks of driverless cars. Computers would have difficulties making ethical（道德的）decisions: if a child ran into the road, would the computer choose to hit the child or turn suddenly and potentially kill the car's passengers? Moreover, I personally find driving fun –I'd miss never driving a car myself. There would also be many other decisions to be made –should children, or drunk people, be allowed in a driverless car by themselves? Or would there need to be a person with a driving license in the car at all times?

    I'm not certain I'd want a driverless car – but it's only a matter of time before they'll become more affordable and popular on our roads.

E

    Artificial intelligence（人工智能）, or AI in short, is the science of giving computers and machines ability to think and work like humans. AI scientists and engineers have made a lot of cool technologies.

    AI is rapidly catching up with the human ability to read faces. As a result, facial recognition（识别）is used a lot in the world. Chinese police use this technology to identify criminals（罪犯）.Once they caught a criminal when he attended a concert. It also checks the ID of ride-hailing（网约车）drivers and lets people pay for things with a smile.

    AI is also used in self-driving cars, which are believed to be the future of driving. Most drivers may wave or nod at passers-by to let them cross the street, but self-driving cars don't have this ability. Carmakers are testing a light signal system to help them "speak" to humans. The system can show what self-driving cars will do. For example, if a driverless car is yielding（让路）, it will flash two white lights side to side. A rapidly flashing light tells passers-by that the car is about to speed up.

    Service Robots also show you know powerful AI is. Imagine this—you come back home from school and your robot housekeeper is waiting for you at the door. After dinner, he teaches you to play the piano, just like a real music teacher. Such thoughts will soon happen in the real world. In the future, more and more service robots will become good home helpers.

    AI is so powerful that it can help human beings and even replace us in many jobs.

    Can dolphins (海豚) talk? Maybe they can not talk with words, but they can talk with sounds. They show their feelings with sounds. Dolphins travel in a group. We call a group of fish a "school". They do not study, but they travel together. Dolphins are mammals (哺乳动物), not fish, but they swim together like fish in a school. Dolphins talk to the other dolphins in the school. They give information to the others. They talk when they are happy, sad or afraid. They say "welcome" when a dolphin comes back to the school. They talk when they play.

    They make some sounds above water. They make many more sounds under water. People cannot hear these sounds because they are very, very high. Scientists make tapes of the sounds and study them. Sometimes people catch dolphins for a large aquarium (水族宫). People can watch dolphins in a show. Dolphins do not like to be away from their school in an aquarium. They are sad and lonely. There are many stories about dolphins. They help people. Sometimes they save somebody's life. Dolphins' meat is good, but people do not like to kill them. They say that dolphins bring good luck. Many people believe this.

    The Earth is about 4, 600 million years old Man lives on the Earth for only 35, 000 years. But we change our Earth in many ways. Many things we do are good, but some are not good for the Earth.

    Water pollution

    A lot of people, birds and fish die each day because of water pollution. Factories pollute the water. As a result (因此), the water in many rivers and lakes is now very dirty.

    Air pollution

    In big cities, factories, cars and buses are the main causes of air pollution. Many people in cities now have health problems. For example, Mexico City used to be a beautiful sunny capital, but today there are many clouds in the sky. And many people get ill because of the polluted air.

    Soil (土壤) pollution

    In order to have a better harvest (收获), some of the farmers use chemicals too much in their fields. That's bad for the soil.

    Hope for the future

    These problems are very serious for our future, so all of us should do something to protect the environment. If we can stop pollution, our Earth will become more and more beautiful.