This sentence means that study can make up for our defects and experience can teach us things that we cannot learn from books or that are inaccurate. Through study, we can better understand the colorful world around us, and more importantly can better know ourselves, that is, what are our strengths and weaknesses, which is difficult for us without study. Additionally, study is incomplete, and we need to experience things around us to test whether what we have learned from books is right or to learn new things because books or any other materials are limited to encompass the whole world.