If you really like this teacher, buy the original. It's estimated that you can't wait for it. What you want is a full set. It must be expensive! Or you can choose other online schools, such as Taoyu.com and other schools, which also offer Japanese courses. Then if you still want to continue your study and are afraid of the expiration, you can choose to postpone it. In any case, it is free to apply for an extension in Yu Tao. You can ask in Hujiang!