A、Because we can succeed only by making mistakes. B、Because it is necessary for us to make mistakes if we want to be successful.

Knowledge can be gotten from many sources. These include books, teachers and practical experience, and each has its own advantages. The knowledge we gain from books and formal education enables us to learn about things that we have no chance to experience in daily life. We can study all the places in the world and learn from people we will never meet in our lifetime, just by reading about them in books. We can also develop our analytical skills and learn how to view and explain the world around us in different ways. In addition, we can learn from the past by reading books. In this way, we won’t repeat the mistakes of others and can build on their achievements.
    Practical experience, on the other hand, can give us more useful knowledge. It is said that one learns best by doing, and I believe that this is true, whether one is successful or not. In fact, I think making mistakes is the best way to learn. Besides, if one wants to make new advances, it is necessary to act. Innovations do not come about through reading but through experimentation. Finally, one can apply the skills and insights gained through the study of books to practical experience, making a meaningful experience more meaningful. However, unless it is applied to real experiences, book knowledge remains theoretical and, in the end, is useless. That is why I believe that knowledge gained from practical experience is more important than that gained from books.