Teachers will design courses for subjects, so that they can clearly know what to test, what to master and what they must know to take this test. Of course, any cross talk or counseling is only an auxiliary means. The key is to be able to grasp the whole knowledge and read and brush it according to the outline and the exam questions over the years.
Of course, it is also very difficult to remember knowledge in a short time after listening to cross talk. Experienced teachers have a higher level and may have a greater grasp of the exam.
Any counseling book has advantages and disadvantages, and its only feature is that it covers everything, but the exam is to test the basic knowledge. Therefore, we should choose what classes to enroll according to our own specific conditions, including the purpose of enrolling in what classes at the beginning.