Let us suppose it is now about A．D. 2100. Let's make believe(假装，假扮) it is about eighty years from now. Of course, things have changed and life is very different.

　　Voyages to the moon are being made every day. It is as easy to take a holiday on the moon today as it was for the people in 1960 to take a holiday in Europe. At a number of scenic (风景优美的) spots on the moon, many hotels have been built. The hotels are air­conditioned, naturally. In order that everyone can enjoy the beautiful scenery on the moon, every room has at least one picture window. Everything imaginable (可以想象的) is provided for entertainment of young and old.

　　What are people eating now? People are still eating food. They haven't yet started to take on heir (继承) supply of energy directly as electrical current or as nuclear power (核能). They may some day. But many foods now come in pill form, and the food that goes into the pill continues to come mainly from green plants.

　　Farming, of course, is very highly developed. Very few people have to work on the farm. It is possible to run the farm by just pushing a few buttons now and then.

　　People are now largely vegetarians (素食者). You see, as the number of people increases, the number of animals decreases. Therefore, the people have to be vegetarians and we are healthier both in our bodies and in our minds, and we know the causes and cure of disease and pain, and it is possible to get rid of diseases. No one has to be ill any more.

Such would be our life in 2100.