The thief disappeared into the crowd .

    Today there are nearly 7. 4 billion people on Earth. By the year 2050 there may be 9. 8 billion. There are many people to feed. We need more and more food.

    One way to produce more food is growing stronger plants. For thousands of years, farmers have made plants better. Every season, they pick the best plants for the next season. It works very slowly. Since 1983, scientists have been able to change plants more quickly by changing their genetic (基因的) material. Foods from plants grown in this way are called genetically modified (转基因的) foods, or GM foods.

    By changing the genetic material of a plant, it is possible to make new plants. Scientists make plants which are strong against plant diseases. They can also help in our diseases: a kind of rice will be grown, for example, which stops people becoming blind.

    Rich countries produce GM foods because they are easy to grow and bring in more money. Poor countries are interested in them because they help produce more food.

    GM plants are not natural. No one knows how good or bad they are. Making GM foods is only one way of feeding people in 2050. There are strong feelings against them because they are unnatural. They may feed people, then hurt them or their children later. But both rich and poor countries are interested in their uses, and they are not going to go away. In 2050, we may think differently about them.

    Life in the year 3044 is very different1life in the 2lst century. We still do many of the things you did, but we do them2. For example, we now have e-friends to help us and keep us company. An e-friend is a machine that looks just3a human being. It can walk and talk and can do almost4we human beings do. My e-friend is a lot like me and we have5fun together. She helps me6my homework and we often go swimming. She is programmed to take care of me if anything7, so I always feel safe when we are together. She can also send me messages, just like old-fashioned emails, and I can download information from her memory. It's great8an e-friend—I am never lonely and I always have someone to talk9.

    I would like to tell you more about life in the year 3044, but I have to send my e-friend to clean up my room. Maybe10I will be able to travel back in time and visit you.