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What will man be like in the future-in 5,000 or even 50,000 years? We can only make guesses, 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 average（平均），men are about three inches（英尺）taller. Again, in the modern world we use 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 eventually we shall need larger ones! This is likely to bring about a physical change to the head, especially the forehead, will grow larger.
Nowadays our eyes are used very often. In fact, we use them so much that 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 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.
But 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 sexes are likely to be bald（光头的）.
Perhaps all this shows that future man will not be a very attractive being to look at! This may well be true. No matter how great the change is, future man will still have a lot in common with us.