Have you ever felt you were being watched? Some new technologies might make you feel that way. Digital billboards（电子屏幕）are able to recognize certain human characteristics （特征）. They have cameras pointed at the people on the street, and can recognize people’s age, a man or a woman. Then a computer inside the billboard uses this information to make ads （advertisements）for the people who are looking at the billboard. For example, if a man passes a billboard showing an ad about women clothes, the computer can change the ad to something such as men’s sporting shoes, to catch the man’s attention.

Although advertisers see this as a great chance to reach their customers, some people feel that this is an invasion（侵犯）of their privacy. However, advertisers say that the billboards will not be able to recognize their face or get any personal information about them.

In fact, this kind of “personal” advertising has already appeared on the Internet. Search engines（引擎）like Google and Bing can follow what we search for. When we have searched for some products and services, companies then pay search engines to use it in ads. So if you search for travel information, you may see ads for airlines and hotels. This kind of advertising has proved to work better than traditional advertising.

In today’s world, people see thousands of ads every day, but they don’t take much notice. Advertisers are trying to change that by personalizing the experience of seeing an ad. So pay attention the next time you see a billboard—it would be talking to you.

What will life be like in 2050? How different are things going to be? Some science and technology experts offer their predictions.

Transportation will look very different in years to come. 【小题1】. Chris Riddell, a famous futurist, predicts that roads in many big cities will be filled with self-driving cars before 2050. People who want to drive themselves may have to pay some money for the pleasure.

According to Riddell, among all new technologies, artificial intelligence (AI) (人工智能) will change our life the most, 【小题2】 And these computers will be able to learn to act like humans. But because of their artificial “brains”, they can learn things faster. “In 2050, We won’t just have humans in the company,” says Riddell. “【小题3】.”

By 2050, there will be more people living on Earth. 【小题4】 Scientist Ian Lowe warns that we need to use clean energy. “We are damaging (破坏) the environment at a great speed,” Lowe says. “We simply don’t know what will happen in the future. 【小题5】 What happens in the future will be the result of our decisions and actions today.”

“The delivery man（送货员）has your food and is on his way.” This is a piece of information you may receive after you order food online. We know that delivery men bring your food to you. Do you believe that self-driving cars—cars without drivers will bring food to you in the near future? That sounds interesting, doesn’ t it?

Now Baidu and Meituan are working together to use self-driving technology (技术) to deliver food. They are going to make some self-driving cars. These companies use the self-driving cars to send group orders. For example, when a company orders food for people working there, a self-driving car will bring all of their orders to the company.

Online food ordering is becoming popular all around China, even in small villages. Till now, about 300 million users use different apps to order food online. Some researchers （研究人员）say that using self-driving cars will be a revolution in the food delivery. They will make a great difference in the future.

Some people think there must be some problems about using self-driving cars to deliver food. For example, self-driving cars can drive well on flat (平坦的) roads, but can they drive well when the road is not flat? People must work out such problems before they can use self-driving cars.

Some people say that we will use self-driving cars in the near future and delivery men will lose their jobs. Do you think so? My answer is “No.” because self-driving delivery cannot bring food to everyone in every city.