As is well known, books teach us to learn life, truth, science and many other useful things. They increase our knowledge, broaden our minds and strengthen our character. In other words, they are our good teachers and wise friends. This is the reason why our parents always encourage us to read more books. Reading is a good thing, but we must pay great attention to the choice of books. It is true that we can derive benefits from good books. However, bad books will do us more harm than good.