If you understand everything in the textbook, why is it necessary to practice?

The basic idea of these review questions is to give you a chance to see if you have noticed and understood the key points of the chapter. You may have to refer back to the text to answer a question; that’s normal and expected. You may have to reread whole sections; that too is normal and expected. However, if you have to reread the whole chapter or have problems with every review question, you should consider whether your style of learning is effective. Are you reading too fast? Should you stop and do some of the Try this suggestions? Should you study with a friend so that you can discuss problems with the explanations in the text?