Cross-professional examination and research requires great efforts, and professional courses start from scratch. Suggest signing up for a remedial class. If you are in a foreign country, you can apply for a remote professional class. If you are from Xi, I suggest you sign up for a good remedial class. In this way, you will gain a lot later. I heard that Xi 'an University Postgraduate Training School is good, you can go and have a look. Many of our classmates reported to the university for consultation, and they all said it was good!