What will man be like in the future — in 5,000 or even 50,000 years from now? We can only make a guess, of course, but we can be sure that he will be different from what he is today. For man is slowly changing all the time.

Let us take an example. Man, even five hundred years ago, was shorter than he is today. Now, on the average, men are about three inches taller. Five hundred years is a relatively (相对地) short period of time, so we may suppose that man will continue to grow taller.

    Again, in the modern world we use our brains a great deal. Even so, we still make use of only about 20% of the brain's capacity (容量.) As time goes on, however, we shall have to use our brains more and more and finally we shall need larger ones! This is likely to bring about a physical change too. The head, especially the forehead, will grow larger.

    Nowadays our eyes are being used too much. In fact, we use them so much that very often they become weaker and we have to wear glasses. But over a very long period of time it is likely that man's eyes will grow stronger.                      

    On the other hand, we tend (有…的趋势) to make less use of our arms and legs. These, as a result, are likely to grow weaker. At the same time, however, our fingers will grow more sensitive (敏感的) because they are used a great deal in modern life.

    What about hair? This will probably disappear from the body altogether in course of time because it does not serve a useful purpose any longer. In the future, then, both men and women are probably to be hairless!

    Perhaps, all this gives the impression that future man will not be a very attractive (有吸引力的) person to look at! This may well be true. All the same, besides these changes, future man will still have a lot in common with us. He will still be a human being, with thoughts and feelings similar to our own.