Effective evaluation is too subjective. If it suits you, it is effective; If not, it is invalid. So, to see if something works, you have to listen and see for yourself. Besides, what I saw with my own eyes may not be true. I also choose a tutor for my children. 100 education. There are all kinds of entanglements before choosing, but after choosing, it feels quite suitable for him to learn and use. This is what people often say. Only the feet know whether the shoes fit or not. You must see and try.