How to improve without time? Anyway, you have to take time out, so it is possible ... Since there is not much time, let's consider it as a test paper simulation method! Set aside concentrated time every day (preferably a whole day, about two hours) to do a set of simulation questions, just like an exam (note, it is best to strictly follow the exam rules), then take a break and correct them by yourself, according to the answers ... The focus is on the wrong questions and write them down. A wrong question is a loophole or deficiency in the knowledge of a book or a paragraph. Go back to the book and understand it thoroughly.