將下面的短文譯成漢語。

　　Man still has a lot to nearn about the most powerful and complex part of his body-the brain.

　　In ancient times men did not think that the brain was the center of mental activity.Aristotle the philosopher of ancient Greece thought that the mind was based in the heart.It was not until the 18th century that men realized that the whole of the brain was involved in the workings of the mind.

　　During the 19th century scientists found that when certain parts of the brain were damaged men lost the ability to do certain things.And so,people thought that each part of the brain controlled a different activity.But modern research has found that this is not so.It is not easy to say exactly what each part of the brain does.