If you want to lay a solid foundation and make gradual progress at a lower level, I recommend the "General Practitioner King", which has both exercises and a summary of knowledge points, and there are many mistakes, so it is suitable for learning and using at the beginning. If you want to practice purely, you can use Qidong Homework, and the number of questions and basic questions are enough. Unit thesis, gold medal in each course, doctor online, and express delivery for senior high school entrance examination are all good. Suitable for lifting.