There are two main channels for people to learn knowledge –from books and from experience.
　　Generally, knowledge gained from books is theoretical, that gained from experience is practical. It is difficult to answer which is more important to we people. It depends on the phases and events of our learning. Knowledge learned from books is instructive, which perhaps cannot learn directly from experience. We often hear thunders and see lightning in the sky, and we can easily find that lightning will be seen sooner than sound will be heard. According to our experience alone, we cannot tell why it had happened. But when we learn some physics in textbooks, we will find the answer clearly that because light travels faster than sound does, it takes less time for light to travel the same distance than for sound. Therefore, book knowledge can inform us some useful theories that can give us general ideas and help us understand the real phenomenon better.
　　In turn, practice knowledge check out the theories gained from books. There is an old Chinese saying that practice is the only criterion of inspecting the truth. So, not all knowledge from books is credible, even false. When Aristotle wrote in his transcripts that the earth is the center of our planets, no one doubts this for centuries. However, when Galileo read about it, he did not suspect it at first, but when he made some observation and research, he found it is not the truth. Then comes the new theory—Sun center theory.
　　In our daily life, we can learn much information from practice. To learn swimming, it is useless to be absorbed in reading skills written in books. Only when you learn it in a swimming pool, can you make it. There are still a lot of things you must learn from your own experience, such as driving a car, riding a bicycle, operating a machine. And the most important is that it is often easier learn knowledge from practice than from books. As far as the average people are concerned, it is natural to learn from experience. Primitive people learned skills hand by hand which is the way they were handed down from one generation to another.
　　Modern people also learn things in practice. In workshops, leading workers teach apprentices carefully; in activity clubs, teachers teach youngsters to be familiar with their hobbies. It is obvious that all of things considered knowledge gained from practice is more close and direct than from the books.
　　Therefore, two kinds of knowledge have importance. For research people, knowledge from books is more important, while for our average people, knowledge from practice is more important. As students, we must first learn knowledge from books well, and at the same time we must have the good sense to tell from what is right and what is wrong.